Class 8

You can Download Static Electricity Questions and Answers, Summary, Activity, Notes, Kerala Syllabus 8th Standard Basic Science Solutions Chapter 20 help you to revise complete Syllabus and score more marks in your examinations.

Kerala State Syllabus 8th Standard Basic Science Solutions Chapter 20 Static Electricity

When some substances are rubbed against each other they can attract other objects. When the substances are rubbed the electrons are exchanged. An atom of a substance gets positive charge on losing electron and negative charge on receiving electron.

Proton, neutron, and electron are the subatomic particles in an atom. Neutron does not possess any charge. Proton have positive charge and electron have negative charge. In any atoms, the number of elect¬ron and proton are equal. So an atom is electrically neutral.

Electrification or charging is the process of converting an object in to electrically charge One. If the electric charge produced in an object remains at the same place in it, it is called static electricity. When a glass rod is rubbed on silk, electrons are lost from the glass rod. Then the glass rod gets positive and silk gets negative charged.

When an ebonite rod is rubbed with wool, ebonite rod gets negative and wool gets positive charged. The metals also charged when rubbed but the charge will spread overall part of the metallic substance. This causes current electricity, there is no static electricity in metals.

Static Electricity Class 8 Kerala Syllabus Properties of electric charges

• Charged bodies attract uncharged bodies.
• Unlike charges attracts each other
• Like charges repel each other As the charged bodies attract uncharged bodies if two bodies attract each other we cannot say certainly both the bodies possess charge. But if two bodies repel each other it is sure that both bodies possess like charge.

The unit of charge is coulomb. Charge is a scalar quantity. The electroscope is the instrument to know the presence of static electric charge. It is an instrument in which a metallic conductor, gold leaves and a metal ball are connected in a glass jar.

The activity to neutralize the charge on a body is known as discharging.

Static Electricity Class 8 Notes Pdf Kerala Syllabus Earthing

Connecting a body to the earth using metallic conductor is known as earthing. On earthing a charged body, electrons pass from the earth to the body or from the body to the earth to neutralize the charge on the body completely. The give or receives electrons at any time and any quantity. So earth is referred to as an electron bank. If a positively charged body is earthed the electrons flow from earth to the body and if it is charged negatively, the electrons flow to the earth.

Static Electricity Class 8 Notes Kerala Syllabus Electrostatic induction

On bringing a charged body near to an object the charge is induced to that body. The redistribution of charges in a body as a result of the presence of another charged body is called electrostatic induction. Due to the presence of charged body, the opposite charge is induced on the other body. Then they are attracted each other. If the bodies are in contact due to attraction the opposite charges are canceled.

Chapter 20 Static Electricity Answers Kerala Syllabus Capacitor

When a metallic plate is placed near another plate which is positively charged, there is an electric field is formed between them. With this arrangement, electric charge can be stored and retained for a long time. The device which can store electric charge in this way is a called a capacitor. The charge is distributed in a conductor would be only on its surface. The amount of charge would be more at the pointed ends.

Class 8 Physics Notes Kerala Syllabus  Lightning

Lightning is the electric discharge between charged clouds in the atmosphere or between charged clouds and the earth

Basic Science Class 8 Electricity And Lightning Kerala Syllabus Lightning conductor

To protect the buildings from lightning, an earthed conductor with pointed end is placed on the highest part of the building. This is lightning conductor.

Methods to protect from lightning

• Do not operate electrical equipment
• Do not lean on the wall of the house.
• Do not stand holding windows bar or grill
• Do not stand beneath tall trees
• Do not take shelter under isolated trees
• Do not stand at open place
• A person struck by lightning should be made to lie in a place where there is good air circulation. In order to prevent blood clotting keep the body warm by massaging. Give artificial respiration and press strongly on the chest to maintain ‘ heartbeat and the person must be taken to a hospital immediately

Static Electricity Textbook Questions and Answers

Basic Science Class 8 Chapter 10 Electricity And Lightning Question 1.
From which one to which does electronic transfer occur when the pair of substances given below are rubbed against each other?
a. Glass rod – Silk doth
b. Ebonite – Wool
Answer:
a. From glass rod to silk
b. From wool to ebonite

Static Electricity Questions And Answers Kerala Syllabus Question 2.
Among the substances given below, which cannot be electrified by friction? Why? Amber, Plastic, Hacksaw blade, PVC pipe.
Answer:
Hacksaw blade. Because it is metal

Static Electricity Class 8 Questions Kerala Syllabus Question 3.
lightning conductors, which are not properly earthed, produce disaster rather than benefit. Justify this statement.
Answer:
Even though all the lightning will not affect the building, if there is lightning conductor the opposite charge of that in the clouds is induced on the pointed end of the conductor. If there is no earthing the flow of electron will be from the building to the conductor or to the building which causes accident

8th Class Biology Notes Pdf Malayalam Medium Kerala Syllabus Question 4.
What are the precautions to be taken for protecting ourselves from lightning?
Answer:

• Do not operate electrical equipments
• Do not lean on the wall of the house.
• Do not stand holding windows bar or grill
• Do not stand beneath tall trees
• Do not take shelter under isolated trees

Static Electricity Class 8 Kerala Syllabus Question 5.
How would you convert a copper plate kept in an electroscope into an arrangement for storing charge for a long time, through induction?
Answer:
Place copper sheet around the leaves of an electroscope. Touch the nob with a charged, body. Opposite charge is formed on the leaves. Opposite charge of it is formed inside the sheet and the same charge is formed outer surface of the sheet. Now the sheet is earthed, the charge on outer surface will be disappeared.

Static Electricity Additional Questions & Answers

Kerala Syllabus 8th Standard Chemistry Notes Malayalam Medium Question 1.
Complete the table

Objects	Electron exchange	Positive	Negative
Glass, silk	From glass rod to silk	….. a …..	Silk
Ebonite, wool	Wool to ebonite	…. b ….	…. c ….
Rubber rod, wool	…. d ….	Wool	…. e…

Answer:
a. Glass
b. Wool
c. Ebonite
d. From wool to rubber rod
e. Rubber rod

Kerala Syllabus 8th Standard Chemistry Notes English Medium Question 2.
When a glass rod is rub with silk electron loses from the glass rod. If we bring another glass rod near to it what can be observed? Give reason
Answer:
They will repel. Same charges repel each other.

8th Standard Chemistry Textbook Kerala Syllabus Question 3.
Tick the correct one
1. Object with same charge attract/repel
2. The charged body attract/ repel the neutral body
3. bodies with different charges attract/repel.
Answer:
1. repel
2. attract
3. attract

Static Electricity Questions And Answers Pdf Kerala Syllabus Question 4.
What is the use of capacitor?
Answer:
To store the charge

Electricity For Class 8 Kerala Syllabus Question 5.
What is earthing?
Answer:
Connecting an object to earth with a conductor is called earthing.

Question 6.
Examine the following figures and mark the point which charge is accumulated.

Answer:

Question 7.
Complete the figure.

Answer:

Question 8.
Why does the pointed edged con-ductors are used as lightning conductor
Answer:
The charge accumulated at the pointed edge easily and discharge it to earth immediately. So the building is not affected by lightning

Question 9.
What are the precautions to be taken when lightning
Answer:

• Do not operate electrical equipment
• Do not lay on the wall of the house.
• Do not stand holding windows bar or grill
• Do not stand beneath tall trees
• Do not take shelter under isolated trees

Question 10.
What are the primary steps to be adopted when a person is struck by lightning
Answer:
A person struck by lightning should be made to lie in a place where there is good air circulation. In order to prevent blood clotting keep the body warm by massaging. Give artificial respiration and press strongly on the chest to maintain heartbeat and the person must be taken to a hospital immediately

Question 11.
What is dielectric
Answer:
The dielectric are the insulators used in between the plates of the capacitor to increase its capacity Eg. Plastic, polyester, air, paper

Question 12.
What is capacitance? What is its unit
Answer:
capacitance is the ability to store the charge in it. Its unit is fared(F).
1F = 10⁶ μF(microfarad) 1F = 10^{12 μ}F (picofarad)

Question 13.
You might have seen iron chains, suspended from the body of lorries and trucks touching the earth. What is this for?
Answer:
These lorries and trucks have to travel a long distance. Sometimes the friction between rod and tire or vehicle and oil in it produces static electricity. This discharge gathers at one end of the truck and it causes sparking and from it the petrol may catch fire. The iron chains suspended from the body of lorries and trucks provide earthing and help to avoid the hazard.

Question 14.
The installation of lightning conductors is not insisted in may tall modern concrete buildings, nowadays. How are they protected from lightning?
Answer:
In tall modern buildings, there are plenty of metal rods inside the concrete work, connecting from the top to bottom of the building and to the earth. Electric charge from the lightning clouds, reaching the building, is conducted safely to the earth through these metal rods. So the building are protected from damage due to lightning discharge

Question 15.
A person takes shelter under a tree during heavy rain. Another person shelters under a coconut tree of same height. Who will be safer during lightning? Why?
Answer:
The person standing under the tree is safer. Electric charge always get concentrated at sharp edges. So more possibility for danger due to lightning is to the man under coconut tree than the. another one

Question 16.
There are two houses nearby, both of them having T.V. antenna pipes. One of these pipes is earthed. Write down the advantages or disadvantages of earthing the pipe.
Answer:
Advantage:
When lightning strikes the antenna it does not affect the house if the antenna pipe is earthed. The electric charge of the lightning goes to the earth through the pipe and so it acts as a lightning conductor.

Students can Download Basic Science Chapter 6 Chemical Changes Questions and Answers, Notes Pdf, Activity in Malayalam Medium, Kerala Syllabus 8th Standard Basic Science Solutions helps you to revise the complete Kerala State Syllabus and score more marks in your examinations.

Kerala State Syllabus 8th Standard Basic Science Solutions Chapter 6 Chemical Changes in Malayalam

Chemical Changes Text Book Questions and Answers

You can Download इंद्रधनुष धरती पर उतरा Questions and Answers, Summary, Activity, Notes, Kerala Syllabus 8th Standard Hindi Solutions Unit 4 Chapter 1 help you to revise complete Syllabus and score more marks in your examinations.

Kerala State Syllabus 8th Standard Hindi Solutions Unit 4 Chapter 1 इंद्रधनुष धरती पर उतरा (चित्र-कहानी)

इंद्रधनुष धरती पर उतरा Summary in Malayalam and Translation

आकाश में रहते रहते मैं ऊब गया हूँ। क्यों न धर्ती पर ही चला जाऊँ!!!

सप्तम एक सुंदर-सी घाटी में उतर आया। दिन-भर वह घाटी में घूमता रहा। अंधेरा होने पर वह एक घने पेड़ के पास पहुंचा।

क्या मैं तुम्हारी टहनियों पर आराम कर सकता हूँ?

तुम मेरी टहनियों पर नहीं रह सकते। यह तुम्हारे लिए सही जगह नहीं।

थका हारा सप्तम आगे बढ़ा। वह एक निर्झर के पास पहुंचा।

आज की रात मैं तुम्हारे पानी में सो जाऊँ?

माफ़ करो भाई। किसी झरने के पानी में इंद्रधनुष कैसे रह सकता है?

सप्तम एक लड़के के पास गया।

क्या मैं तुम्हारे घर में आराम कर सकता हूँ?

क्यों नहीं? तुम ज़रूर यहाँ आराम कर सकते हो। अब तो मेरा अपना इंद्रधनुष होगा।

झोंपड़ी के अंधकार में सप्तम के सुंदर रंग दिखाई नहीं दे रहे थे। वह उदास हो गया।

तुम अपने आकाश से भाग क्यों आए?

यहाँ के पेड़-पौधे, नदियाँ, पहाड़ और फल-फूल आकाश से कितने सुंदर दिखाई देते हैं !

अपने घर में मुझे रहने दिया। बहुत शुक्रिया। अब मुझे वापस जाना है।

लड़के ने उसे विदा दी। वर्षा की बूंदें बरसने लगीं। पूर्व में सूर्य की किरणें झलकने लगीं। सात रंगोंवाला इंद्रधनुष चमकने लगा। सप्तम फिर से अपना घर पहुँच गया था।

इंद्रधनुष धरती पर उतरा शब्दार्थ Word Meanings

You can Download Measurements and Units Questions and Answers, Summary, Activity, Notes, Kerala Syllabus 8th Standard Basic Science Solutions Chapter 8 help you to revise complete Syllabus and score more marks in your examinations.

Kerala State Syllabus 8th Standard Basic Science Solutions Chapter 8 Measurements and Units

In olden days different scales were used for measuring length in different countries. Vaara, One forearm (muzham) etc are some of such units. These units were not accurate. For solving this problem a standard scale of a definite length has been recognised world widw for measuring length. This standard scale is the unut of length. The basic unit of length is metre (m).

Smaller units of length

Examine the metre scale. You can see small measurements on it. These are centimetre (cm) and millimetre(mm)
1m = 1oocm 1cm=1omm
The smallest length that can be accurately measured using a metre scale is its least count.

Thickness of paper

We cannot measure the thickness of the paper even with these small units. Take too sheets of paper and pile it up to make a bundle. Measure the height of this bundle using a scale. If it falls in between two markings, make suitable changes in the number of sheets. Then measure its height. By dividing this height by the number of sheets, we will get the thickness of a sheet of paper.

Similarly to find out the thickness of thin wire roll it on a pencil and mea-sure the length of ten rolls Then divide it by 10.

Length of a curved line

To measure the length of the curved line put a thread on it and measure its length using a meter scale

Distance of a sphere

A ball kept in between two wooden blocks, whose diameter is to be measured. Then we will get its diameter.

Various measurements of length

The basic unit of length is metre. Smaller units like centimetre (cm), millimetre (mm), micrometre (micron – ™ nano-metre (nm) are also used in certain situa-tions for convenience. We use a bigger unit like kilometre (km) to measure the distance between two places. Units like astronomical unit (AU), light year (ly) are also used to measuring distance to planets or stars.

Measurement And Units In Physics Class 8 Questions And Answers Mass

Mass is the measure of quantity of matter contained in it. The basic unit of mass is kilogram(kg).

Except kilogram, milligram(mg), gram(g), quintal, tonne are also the units of mass.

Measurement And Units In Physics Class 8 Kerala Syllabus  Time
The symbol is s.
60s = iminute; 6ominute = 1 hour One second is 1/ 86400 part of an average solar day.

Fundamental units

There are some quantities which are not related to one another and cannot be expressed using other quantities. Such quantities are fundamental quantities. The units of the fundamental quantities are the Fundamental Units. The system based on these fundamental units is the | International System of Units. Its short form is SI Units.

Measurements And Units Class 8 Notes Kerala Syllabus Derived unit

Units which are expressed in terms of fundamental units or those units which are dependent on fundamental units are derived units.
Ex. Area = length x breadth

Unit of area = unit of length x unit of breadth = m xm = m².

Salient features of SI units

1. Unified units
2.  Internationally accepted
3.  Adequate to express all physical quantities.

Measurement And Units In Physics Class 8 Notes Density and volume

The space occupied by a body is referred to as its volume.
The unit of volume is cubic metre (m³)

Mass per unit volume of substance is its density. Density = mass/volume Unit of density = unit of mass/unit of volume = kg/m³

The rules to be followed while writing units

We have to observe certain rules according to international standards while using these units and their symbols. They are given below:

1. The symbols of units are normally written using small letters in the English alphabet, eg. m (metre), s (second), kg (kilogram)
2. But there are certain occasions on which capital letters of the English alphabet are used as symbols. The units named after persons are written like this.
3. While writing the names of units never use capital letters, eg. kelvin (correct) Kelvin (wrong) newton (correct) Newton (wrong)
4. Never use the plural form for symbols, eg. 10 kg (correct) 10 kgs (wrong) 75 cm (correct) 75 cms (wrong)
5. Never use full stop or comma after a
   symbol except at the end of a sentence. eg. 75 cm is the length of a table, (correct) 75 cm. is the length of a table, (wrong),
6. While writing derived units a slash (/) is used to denote division. But never use more than one slash in one derived unit. eg. m/s1 (correct) m/s/ s (wrong)
7. When a derived unit is expressed as the product of other units use a dot or a space between them. eg. N.m or Nm
8. 8. Do not mix the name of a unit with the symbol.
9. While writing units along with a value, there must be single space between them.
10. Never use more than one unit to express a physical quantity.

Measurements and Units Textbook Questions and Answers

Units And Measurements Class 8 Kerala Syllabus Question 1.
Write down the following units in the ascending order of their values
a) mm nm cm µ m.
b) 1 m 1 cm 1 km 1 mm
Answer:
a. nm → µ m → mm → cm
b. 1 mm → 1 cm → 1 m → 1 km

Basic Science Question Answer Chapter Wise Class 8 Question 2.
Which of the following units does not belong to the group?
a) kg mg g mm
b) m mm km mg
Answer:
a. mm
b. mg

Chemistry Textbook For Class 8 Kerala Syllabus Question 3.
Imagine that the distance from school to your friend’s house is 2250 m. State this in kilometres.
Answer:
2\(\frac{1}{4}\) km or 2.25 km

8th Class Physics Question And Answers Kerala Syllabus Question 4.
Convert the following units, into SI units without changing their values.
a. 3500 g
b. 2.5 km
c. 2 h
Answer:
a. 3.5 kg
b. 2500 m
c. 7200 s

Measurements and Units Additional Questions and Answers

Kerala Syllabus 8th Standard Notes Physics Question 1.
Take a small quantity of solution A and solution B in a jar. Density of A is 2 kg/m³ and density of B is 5 kg/m³. Which of these flot above the jar ? Give reasion.
Answer:
Solution A
Density of A is less than the density of B. So solution with less density floats above the solution that has high density.

Class 8 Chemistry Chapter 1 Kerala Syllabus Question 2.
Find out the given word pair relation; and fill in the blanks.
a. Length : m ; Volume :………
b. Displacement : m ; Acceleration:…………….
Answer:
a. m³
b. m/s²

Basic Science Class 8 Solutions Kerala Syllabus Question 3.
a. What is the basic unit of time?
b. What do you mean by one Solar day?
c. How much time earth will take to revolve once around the sun?
Answer:
a. Second
b. A day or a solar day is the time period from one noon to the next noon.
c. One year (365 days)

Class 8 Science Notes Pdf State Syllabus Question 4.
Find out odd one. Justify your answer?
a. meter, kilogram, kilogram/ meter³, second
b. Length, volume, mass, time
c. Volume, mass, density accelaration.
Ans:
a.kilogram/meter³ – meter, kilogram, second are basic units, kilogram/meter³ is unit of volume.
b. Volume – Volume is a derived quantity and others are basic quatities.
c. Mass – Mass is a basic quantity and others are derived quantity.

Class 8 Physics Kerala Syllabus Question 5.
What is meant by least count of a metre scale?
Answer:
The smallest length that can be accurately measured using a metre scale is its least count. The least count is 1mm when metre scale is used.

Basic Science Class 8 Pdf Notes Kerala Syllabus Question 6.
Mention a method to measure the thickness of a paper sheet.
Answer:
Take 100 sheets of paper and pile it up to make a bundle. Measure the height of this bundle using a scale. If it falls in between two markings, make suitable changes in the number of sheets. Then measure its height. By dividing this height by the number of sheets, we will get the thickness of a sheet of paper.

Hsslive Guru 8th Class Physics Kerala Syllabus Question 7.
Using following objects how can you measure the diameter of a ball?
hall, two wooden blocks, metre scale
Answer:
The ball is kept in between two wooden blocks as shown in the figure whose diameter is to be measured.

Basic Science Class 8 Kerala Syllabus Question 8.
Fill in the blanks
a. 1 nm = ….. m
b. 1 km = …….cm
c. 1000g = …….kg
d. one light year = …… km
e. 60 sec = …… minute
Answer:
a. 1 nm = 10^-9 m
b. 1 km = 10⁵
c. 1000g = 1kg
d. one light year = 365 × 24 × 60 × 60 × 10⁵ km
e. 6o sec = 1 minute

Chemistry Class 8 Kerala Syllabus Question 9.
Calculate how many seconds in a solar day.
Answer:
24 ×60 × 60s

Std 8 Biology Notes Malayalam Medium Kerala Syllabus Question 10.
Explain the derived units with examples.
Answer:
Units which are expressed in terms of fundamental units or those units which are dependent on fundamen¬tal units are derived units.
Ex . Area = length × breadth=m × m = m²

Question 11.
Tabulate the fundamental quantities and their units.
Answer:

Question 12.
What are the salient features of SI units.?
Answer:

• Unified units
• Internationally accepted
• Adequate to express all physical quantities.

Question 13.
Find the volume of a box having length 2m,breadth lm and height 0.5m
Answer:
volume = length × breadth × height =2 × 1 × 0.5 = 1 m³

Question 14.
Will the mass be same if you take one thermocol and a wooden block of same volume?
Answer:
No. Mass/Volume is density. The density of thermocol is lesser than that of wooden block. The mass will not be the same.

Question 15.
Take one jar with salt water and into both jars. In which jar the egg floated over the liquid. Justify your answer.
Answer:
In the jar having salt water because it has more density.

Question 16.
Tabulate following units and symbols
a. Length
b.Mass
c. Potential difference
d. Force
e.Pressure
f. Time
g.Density
Answer:

Question 17.
Choose the derived quantities from following.
a. Length
b. volume
c. time
d. temperature
e. density
f. velocity
g. intensity of light
Answer:
volume, density, velocity

Question 18.
Tabulate two units connected to the name of personals
Answer:

Question 19.
Find the density of an object of mass 60 kg a having length 5m breadth 3m and height 2m.
Answer:
density =mass ÷ volume
\(=\frac{60}{5 \times 3 \times 2}=\frac{60}{30}=2 \mathrm{kg} / \mathrm{m}^{3}\)

Question 20.
Find the volume of a brick which has a length, breadth and height of 3m, 2m and 4m respectively.
Answer:
Volume = Length × breadth × height = 3 × 2 × 4 = 24m³

Question 21.
How to find the area of irregular surface? Explain with example.
Answer:
The area of irregular surface can be calculated by using graph paper.

Question 22.
How do you find out the diameter of a torch cell
Answer:
Place the cell between two wooden blocks tightly. Find out the distance between the two faces of the blocks, touching the cell using a metre scale. This reading gives the diameter of the cell.

Question 23.
The length of a room is 8m and the breadth ia 5m. Calculate the area of the room.
Answer:
Aiea = length × breadth = 8m × 5m = 40m²

Question 24.
What is meant by density of a substance?
Answer:
Density is the mass of a substance having unit volume. If the mass of the substance is M and V is its volume,
then \(\frac{M}{V}\)

Question 25.
Find out the fundamental units from the following table and mark them. Find out which unit is used to measure each of the physical quantity.

• Ampere
• Metre/second
• Kilogram
• Kilogram/metre
• Mole
• Kelvin
• Metre³
• Kilogram metre/second

Answer:
Fundamental units

• Ampere
• Kilogram
• Mole
• Kelvin

Physical quantity

• Ampere – Electric current
• Kilogram – Mass
• Mole – Amount of substance.
• Kelvin – Temperature

Students can Download Maths Chapter 6 Construction of Quadrilaterals Questions and Answers, Notes Pdf, Activity in Malayalam Medium, Kerala Syllabus 8th Standard Maths Solutions helps you to revise the complete Kerala State Syllabus and score more marks in your examinations.

Kerala State Syllabus 8th Standard Maths Solutions Chapter 6 Construction of Quadrilaterals in Malayalam

Construction of Quadrilaterals Text Book Questions and Answers

You can Download मेरी ममतामई माँ Questions and Answers, Summary, Activity, Notes, Kerala Syllabus 8th Standard Hindi Solutions Unit 1 Chapter 1 help you to revise complete Syllabus and score more marks in your examinations.

Kerala State Syllabus 8th Standard Hindi Solutions Unit 1 Chapter 1 शाहंशाह अकबर को कौन सिखाएगा? (लोककथा)

शाहंशाह अकबर को कौन सिखाएगा? पाठ्यपुस्तक के प्रश्न और उत्तर

8th Standard Hindi Notes Pdf 2021 Kerala Syllabus प्रश्ना 1.
“बहुत-सी ऐसी चीजें हैं जिनके बारे में मैं नहीं जानता।” इस कथन से अकबर का कौन-सा मनोभाव प्रकट होता है?

उत्तर:
बादशाह अकबर की सादगी इसमें देख सकते हैं। बादशाह होने पर भी वे कुछ न कुछ सीखना चाहते हैं। ज्ञान पाने की आकांक्षा हम इसमें देख सकते हैं।

Kerala Syllabus 8th Standard Hindi Notes Pdf प्रश्ना 2.
बीरबल समाज के विभिन्न प्रकार के लोगों को दरबार में बुला लाया। कारण क्या होगा?

उत्तर:
बीरबल समझता था कि हर एक व्यक्ति में कुछ न कुछ हुनर है। मानव अपने आसपास के लोगों से कुछ न कुछ सीख सकता है। बीरबल बादशाह अकबर को ये बातें समझाना चाहता था।

8th Class Hindi Textbook Questions And Answers Kerala Syllabus प्रश्ना 3.
“हमेशा ही सीखता हूँ।” इससे क्या मतलब है?

उत्तर:
इसका मतलब है कि मानव मृत्युपर्यंत कुछ न कुछ सीखता रहता है। मानव का ज्ञान कभी संपूर्ण नहीं होता। हमेशा उसे कुछ सीखने को बाकी रहता है।

8th Standard Hindi First Chapter Kerala Syllabus प्रश्ना 4.
यह बूढ़ी महिला किन-किन की प्रतिनिधि हो सकती है?

उत्तर:
यह बूढ़ी महिला माताओं की प्रतिनिधि हैं। माँ ही सबकी पहली और श्रेष्ठ गुरु हैं।

शाहंशाह अकबर को कौन सिखाएगा? Textbook Activities

कहानी पढ़ी।

Kerala Syllabus 8th Standard Hindi Notes  प्रश्ना 1.
इसमें मुख्य पात्र कौन-कौन हैं और उनकी वेश-भूषा कैसी हैं?

उत्तर:
इसमें मुख्य तीन पात्र हैं- बादशाह अकबर, बीरबल और बूढ़ी महिला। बादशाह की वेशभूषा राजकीय हैं। राजसी कुर्ता और पाइजामा। सिर पर राजसी पगडी। तलवार कमर पर टाँग रही है। आभूषण पहने हैं। बीरबल ने विद्वानों के समान वेश धारण किया है। बूढ़ी महिला ने सलवार पाजामा पहन रखी है।

8th Standard Hindi Textbook Pdf Kerala Syllabus प्रश्ना 2.
इस कहानी के कितने प्रसंग है? वे कौन-कौन से हैं?

उत्तर:
इस कहानी के मुख्य दो प्रसंग हैं- पहला; राजदरबार में बादशाह विद्वानों को देख रहे हैं। दूसरा प्रसंग में बीरबल समाज के विभिन्न तबकों के लोगों को दरबार में उपस्थित करते हैं।

Kerala Syllabus 8th Standard Hindi Guide प्रश्ना 3.
अब इन तालिकाओं की पूर्ति करें।

उत्तर:

Class 8 Hindi Notes Kerala Syllabus प्रश्ना 4.
प्रत्येक प्रसंग में इस कहानी के पात्रों के बीच का संवाद क्या होगा? किसी एक प्रसंग का संवाद तैयार करें।

उत्तर:
बादशाह : बीरबल, इन सबका क्या मतलब है? मेरा महल राज्य की आधी जनता से भर दिया?
बीरबल : माफ़ी चाहता हूँ, जहाँपनाह। मैंने तो आपके आदेशों का पालन किया है।
बादशाह : तो ये सब?
बीरबल : हुजूर, गुस्ताखी माफ़ हो।
बादशाह : फ़रमाइए।
बीरबल : यहाँ मौजूद हर व्यक्ति में कुछ न कुछ हुनर हैं जो दूसरों को कुछ सिखा भी सकते हैं।

Kerala Syllabus 8th Standard Hindi Textbook प्रश्ना 5.
कहानी को एकांकी के रूप में बदलकर लिखें।

उत्तर:
बादशाह अकबर को कौन सिखाएगा? (एकांकी)
पात्र:
अकबर : आयु 45 साल। राजकीय पोशाक।
बीरबल : आयु 45 साल। धोती, कुर्ता, पगड़ी।
3-4 विद्वान : आयु 50-60, धोती, कुर्ता, पगड़ी।
किसान : 50 वर्ष की आयु, धोती और बनीयान।
लिपिक : 40 वर्ष की आयु, धोती और कुर्ता।
महिला : 80 साल की आयु, सलवार ।
[बादशाह अकबर का दरबार । सम्राट अकबर सिंहासन पर तशरीफ़ रखे हैं। बीरबल और कुछ अन्य विद्वान दरबार में चर्चा में मग्न हैं।]
अकबर : (बीरबल की ओर मुड़कर) बीरबल, मैं बहुत चतुर नहीं हूँ। बहुत सी ऐसी चीजें हैं जिनके बारे में मैं नहीं जानता। मैं हर चीज़ को सीखना चाहता हूँ। कल से मेरी पढ़ाई शुरू हो, इसका इंतज़ाम करो।
बीरबल : जहाँपनाह, जैसे आपका हुक्म। (पर्दा गिरता है)
[अकबर का दरबार बच्चे, बुजुर्ग, गृहणियाँ, धोबिनें, किसान, कचरा बीननेवाले, दुकानदार, लिपिक, विद्वान आदि से भरा है। बीरबल दरवाज़े पर खड़े हैं। बादशाह दरबार में आते हैं। सब लोग झुककर बादशाह को प्रणाम करते हैं। दरबार की भरी भीड़ को देखकर बादशाह क्रोधित हो जाते हैं।]
अकबर : बीरबल, इन सबका क्या मतलब? मैंने तुमसे ऐसे लोगों को लाने के लिए कहा था जो मुझे कुछ सिखा सकें। और तुमने मेरा महल राज्य की आधी जनता से भर दिया? अब जवाब दो।
बीरबल : (शांत भाव से) माफ़ी चाहता हूँ, जहाँपनाह। मैंने तो बस आपके आदेशों का पालन किया है। गुस्ताखी माफ़ हो, पर क्या जहाँपनाह, रेत में घंटों खेलकर अपना मनोरंजन करना जानते हैं?
अकबर : (बौखलाते हुए) नहीं! पर इससे क्या?
बीरबल : क्या आप किसी गरीब आदमी की आमदनी में घर चला सकते हैं? या क्या आप जानते हैं कि कपड़ों से दाग कैसे हटाया जाता है?
अकबर : (शांति से) कतई नहीं।
बीरबल : क्या आप जानते हैं कि बुवाई कब होती है? फसल को पानी कब देना है? या कचरे से उपयोगी चीज़ों को कैसे छाँटना है? या कहाँ हरे-भरे चराहगाह हैं? हमारी फ़सलों को बढ़िया दाम कहाँ मिलेगा? या किसी शब्द को इतनी खूबसूरती से कैसे लिखें कि वह चित्र जैसा लगे?
अकबर : (गुस्से से) नहीं, नहीं, नहीं। हज़ार बार नहीं।
बीरबल : (शांति से) तब जहाँपनाह, इस दरबार में मौजूद हर शख्स को कुछ न कुछ हुनर है, कुछ ज्ञान है, दिल या दिमाग की कोई खासियत है। तो सभी शिक्षक भी हैं और विद्यार्थी भी।
अकबर : (हँसते हुए) तब तो तुम भी एक विद्यार्थी हो बीरबल? हा… हा… हा… मैं तो सोचता था कि तुम्हें कोई कुछ नहीं सिखा सकता।
बीरबल : बात इससे उलट है जहाँपनाह, मैं तो हमेशा ही सीखता हूँ।
[बीरबल भीड़ के बीच से एक बूढ़ी महिला का हाथ थामकर धीरे से अकबर के सामने आते हैं।]
बीरबल : हुजूर, ये मेरे पहले और श्रेष्ठ गुरुओं में से एक हैं। (बूढ़ी महिला शाहंशाह को सलाम करती है।)
महिला : हुजूर, बुद्धिमान व्यक्ति जानते हैं कि सब कुछ सीख जाना संभव नहीं है। लेकिन सबको यह सीखना चाहिए कि अच्छा इंसान कैसे बन जा सकता है।’
(अकबर बूढ़ी महिला के सामने अदब से झुकते हुए बीरबल से) .
अकबर : तुम सच में भाग्यशाली हो जो तुम्हें इतनी समझदार गुरु मिली।

शाहंशाह अकबर को कौन सिखाएगा? मेरी रचना में

1. उचित चौकोर में ✓ लगाएँ।

2. रंगमंच:
रंग सज्जा का विवरण है।

3. पात्र:
आयु, वेषभूषा, चाल – चलन
हाव-भाव का संकेत है।

4. कथोपकथन:
संवाद पात्रानुकृल है


भाषा स्वाभाविक है।

इन वाक्यों पर ध्यान दें:

हर शख्स आपको कुछ न कुछ सिखा सकता है।
हरेक ऐसा कुछ जानता है।
क्या आप जानते हैं?

8th Standard Hindi Notes State Syllabus प्रश्ना 1.

उत्तर:

शाहंशाह अकबर को कौन सिखाएगा? पोल खुल गया…!

Std 8 Hindi Kerala Syllabus प्रश्ना 1.

उत्तर:

शाहंशाह अकबर को कौन सिखाएगा? Summary in Malayalam and Translation

→ शाहंशाह अकबर गंभीर ……………. इतजाम करो ।

→ अगली सुबह जब ……………………… लोग थे ।

→ इन सब का क्या अब जवाब दो ।

→ माफ़ी चाहता हूँ करना जानते है ।

→ नही पर उससे ने जवाब दिया ।

→ क्या जहाँपनाह यह होकर चिल्लाए ।

→ तब जहाँपनाह ओर विदुयत्रि भी ।

→ शाहंशाह समझा नही सिखा सकता ।

→ बात इससे उलट गुरुओं में से है ।

→ बृटी महिला ने बन जा सकता है ।

→ शाहंशाह बूटी मालिमा समजदार गुरु मिलीं ।

शाहंशाह अकबर को कौन सिखाएगा? शब्दार्थ Word meanings

You can Download Solutions Questions and Answers, Summary, Activity, Notes, Kerala Syllabus 8th Standard Basic Science Solutions Chapter 15 help you to revise complete Syllabus and score more marks in your examinations.

Kerala State Syllabus 8th Standard Basic Science Solutions Chapter 15 Solutions

Solutions Textbook Questions and Answers

Kerala Syllabus 8th Standard Chemistry Notes Question 1.
Given below are some solutions. Identify and write down the solvent and the solute present in them. (Hint: Those present in large amount is the solvent and that in small amount is the solute).

Answer:

Solution	Solvent	Solute
Saltwater	Water	Salt
Ornamental gold	Gold	Copper
Soda water	Water	CO2
Dilute hydro­chloric acid	Water	Hydrochlo­ric acid

Basic Science For Class 8 Chapter 15 Kerala Syllabus Question 2.
Haven’t you noticed the caption “Shake well before use” in certain medicine bottles?
a. To which class do the substances in them belong to? (Colloid, Solution, Suspension)
b. What is the relevance of such instructions on these bottles?
Answer:
a. Suspension
b. It is used after shaking well because it is settled down after a long time.

8th Class Biology Notes Pdf Malayalam Medium Question 3.
Given below are some activities and observations done by a student using samples of dilute rice water, saltwater, and muddy water.

a. Complete the table with the missing observations, 3
b. Classify these samples into solution, colloid, and suspension.
Answer:

8th Class Biology Notes Pdf Kerala Syllabus Question 4.
There are numerous instances in daily life where solutions are being used. Tabulate some of them.
Answer:

• To make artificial soft drinks
• To make coffee, tea, and juices
• For painting
• Plastering with cement

8th Standard Chemistry Notes Pdf Kerala Syllabus Question 5.
You are now familiar with different types of solutions.
a. What is the difference between saturated and supersaturated solutions?
b. How will you prepare a supersaturated solution of common salt?
c. Unsaturated and supersaturated solutions of copper sulfate are prepared in separate beakers and a crystal of copper sulfate is dipped into each one of them. What would be the observation after a day? Give reasons.
Answer:
a. Saturated solution – The solution in which maximum amount of solute is dissolved A solution which contains more amount of solute than that is required to saturate it is known as Supersaturated solution.
b. Prepare a saturated solution dissolving salt in water. Then the solution is heated and dissolves more solute in it.
c. The size of crystal in the Supersaturated solution increases. This is because of the excess solute stacked on the crystal.

8th Class Chemistry State Syllabus Question 6.
Classify and tabulate the mixtures given below into solution, colloid, and suspension:
Milk, fog, atmospheric air dilute acid, lime water, ink, smoke.
Answer:
Solution:- Dilute acid, atmospheric air
Colloid:- Milk, Smoke, Fog,
Suspension:- Lime water

Solutions Additional Questions & Answers

Hsslive Guru Chemistry 8 Kerala Syllabus Question 1.
Tabulate the components of solution given below.
(saltwater, soda water, ornamental gold, air)
Answer:

Solution	Components
Saltwater	Salt, Water
Soda water	C02 Water
Ornamental gold	Gold, Copper
air	Nitrogen, Hydrogen, CO2, Oxygen, etc

8th Standard Physics Notes Pdf Kerala Syllabus Question 2.
Complete the table.

Answer:
a. Solid
b. Gas
c. Liquid
d. Liquid
e. Liquid
f. Solid
g. Liquid
h. Liquid

Basic Science Class 8 Chapter 15 Kerala Syllabus Question 3.
A child took 3 glasses of equal quantity of water and put half teaspoon salt in one glass and two teaspoon salts in the other. Which is the concentrated solution? Justify your answer.
Answer:
The concentrated solution is in the second glass because the amount of solute is greater in quantity in a concentrated solution

Kerala Syllabus 8th Standard Physics Notes Question 4.
What are the factors affecting the solubility?
Answer:
The nature of solute and the temperature

Kerala Syllabus 8th Standard Chemistry Notes Malayalam Medium Question 5.
Classify the following mixtures as Homogeneous and Heterogeneous
Sugar solution, muddy water, mixture of water and kerosene, salt solution, air, smoke
Answer:

Homogeneous	Heterogeneous
Sugar solution	Mixture of water anc kerosene
Salt solution Air	Muddy water Smoke

8th Class Biology Notes Pdf Kerala Syllabus Question 6.
Tabulate the two differences of solution and colloid.
Answer:

Solution	Colloid
The size of particle solute is very less	The size of particle is of comparatively larger
Cannot scatter the light, therefore, it is not visible	Scatter the light and therefore path of light is visible

Basic Science Class 8 Ch 15 Kerala Syllabus Question 7.
Tabulate the differences between solution and suspension.
Answer:

Solution	Suspension
Size of the particle very small	Can be seen by nak­ed eye
Cannot scatter the beam of light	Scatter the beam of light
Cannot separate by filtration	Can be separated by filtration
Particles are not se­ttled down when ke­ep if undisturbed	Particles are settled down

Kerala Syllabus 8th Standard Biology Notes Malayalam Medium Question 8.
Why does the path of light seen when dust particles are spread in cinema theatre and smart room.
Answer:
When dust particles are spread in air the air becomes suspension. Then it can scatter the light and so the path can be seen

Scert Class 8 Science Notes Kerala Syllabus Question 9.
What is meant by stabilizer; give example.
Answer:
The soft drinks available in market do not settle down even after prolonged storage. To retain as such for long time without settling down some chemicals are added to it. These are called stabilizers.
Eg. Brominates vegetable oil.

Basic Science Class 8 Solutions Kerala Syllabus Question 10.
Explain what are saturated and supersaturated solution?
Answer:
The solution obtained by dissolving maximum amount of solute at a given temperature is known as saturated solution. A solution which contains more amount of solute than that is required to saturate it is known as supersaturated solution.

8th Standard Chemistry Textbook Kerala Syllabus Question 11.
How can we prepare the supersaturated solution of salt?
Answer:
Prepare a saturated solution dissolving salt in water. Then the solution is heated and dissolves more solute in it

Class 8 Basic Science Chapter 15 Kerala Syllabus Question 12.
What are crystals; How can we make growing crystals?
Answer:
Prepare a saturated solution of a sol-ute like copper sulfate. When we allow it to evaporated slowly, the crystals are appeared. Select a suitable crystal and hang it in the solution with a twain. After a few days, the crystal can be seen grown as well.

Question 13.
Collect the names of the preservative commonly used and write its the side effects.
Answer:
Common salt, sugar, acetic acid, sodium meta bisulfate. Overuse of salt causes hypertension (blood pressure). Use of sugar effects badly on diabetic patients. Acetic acid causes acidity.

Question 14.
What is “Tyndall effect”
Answer:
The colloidal particles can scatter light and so we can see them. This is Tyndall effect.

Students can Download Maths Chapter 2 Equations Questions and Answers, Notes Pdf, Activity in Malayalam Medium, Kerala Syllabus 8th Standard Maths Solutions helps you to revise the complete Kerala State Syllabus and score more marks in your examinations.

Kerala State Syllabus 8th Standard Maths Solutions Chapter 2 Equations in Malayalam

Equations Text Book Questions and Answers

You can Download life’s Mysteries in Little Chambers Questions and Answers, Summary, Activity, Notes, Kerala Syllabus 8th Standard Basic Science Solutions Chapter 1 help you to revise complete Syllabus and score more marks in your examinations.

Kerala State Syllabus 8th Standard Basic Science Solutions Chapter 1 life’s Mysteries in Little Chambers

life’s Mysteries in Little Chambers Questions and Answers

Microscope

The Microscope is a device used to magnify objects. The main parts of a microscope are Eye piece, Knobs, Objective Lens, Stage and clip, Diaphragm, Mirror etc.

The microscopes in which more than one lens is used are called compound microscopes: In a microscope there are two planes for the regulation of light. A plane mirror to reflect the sunlight and a concave mirror to reflect artificial light. The lens of the condenser that is fitted on the lower side of the stage focuses light on the material to be observed. Diaphragm regulates the intensity of light.

Indicators (Text Book Page No:9)

Life’s Mysteries In Little Chambers Kerala Syllabus 8th Question 1.
Why is a mirror fixed in a microscope?
Answer:
The Mirror is fixed to focus light on the objects to be observed.

Kerala Syllabus 8th Standard Biology Notes Question 2.
Why do we use a slide made of glass to place the material to be observed?
Answer:
A transparent surface is required to pass light of the material to be observed. So glass slide is used to place it.

Magnification Power of Microscope

Magnification Power is marked as tox and 45X in the objective lens and eyepiece. The magnification power of a microscope is the product of the numbers seen in the objective lens and eyepiece.
Preparation of Observation Material

Following are the steps in the preparation of a slide to observe plant cells.

1. Put the observable material in a petridish containing water to prevent dehydration.
2. Take thin cross sections of the material
3. Put the sections to a watch glass con-taining water.
4. Put the thinnest and complete sections to a watch glass containing stain.
5. Add one or two drops of glycerin to the slide to avoid drying up of the material.
6. Wash the stained section with clean water and place it in the glycerine on the slide.
7. Put a cover glass over the material.
8. Wipe out the excess glycerin using tissue paper.

Discovering of Cell

Robert Hooke discovered cells for the first time. The branch of science that deals with cells is called cell biology. The re markable findings that paved way for the development of cytology and the concerned scientists are indicated below.

• Robert Brown – Discovered Nucleus (1831)
• M. J. Schleiden – Discovered Plant Cells (1838)
• Theodor Schwann- Discovered Animal Cells (1839)
• Rudolf Virchow – Inferred that new cells arise only from existing cells (1858)

8th Class Biology Notes Pdf Kerala Syllabus Cell Theory

M.J. Schleiden and Theodor Schwann are the founders of cell theory. Mainly two concepts are put forward by cell Theory.

• All living body is made up of cells.
• Cells are the structural and functional units of organisms.

8th Class Biology 1st Chapter Kerala Syllabus Question 3.
What are the functions performed by cells?
Functions of Cells

• Resist foreign particles,
• Synthesis biomolecules.
• Release energy from nutrients

Structure of cell is suitable to perform various biological functions. There are different parts inside the cell for this purpose.

1. Nucleus – Centre of the cell.
2. Ribosome – Helps in protein synthesis
3. Chloroplast – Helps in photo synthesis
4. Mitochondrion – Centre of energy production, storage and distribution.
5. Vacuole – Stores water, salts, excretory materials etc.
6. Golgi complex – Stores enzymes, hormones, mucous etc in small vesicles.

Basic Science Class 8 Pdf Notes Kerala Syllabus Question 4.
Complete the illustration given below related to different kinds of organelles.

Hss Live Guru 8th Biology Kerala Syllabus Nucleus

Innumerable life processes take place within the cell. The biomolecules that control and coordinate these processes are synthesized under the control of the genes in the chromatin network of the nucleus.

Major parts of the nucleus are nucleoplasm, nuclear membrane, chromatin reticulum, nuclear pore, nucleolus etc.

Nucleoplasm is the fluid part of the nucleus. Nuclear membrane is the double-layered membrane that surrounds the nucleus. The minute pores in the nuclear membrane are called nuclear pores. The spherical nucleolus seen in the nucleus play a major role in the synthesis of ribosome. The chromatin reticulum seen as a network in the nucleoplasm encloses genes.

Prokaryotes and Eukaryotes

There is no definite nucleus in the cell of bacteria, cyanobacteria and mycoplasma etc. There are called prokaryotes. But in the cells of amoeba, plants, and animals a well defined nucleus is present. These organisms are called eukaryotes.

Biological Membranes

Cells are covered by membranes. They regulate the exchange of materials between cells and between cell organelles and cytoplasm. These membranes are called selectively permeable as they pass only the essential materials across them.

Indicators (Text Book Page No: 17)

Kerala Syllabus 8th Standard Physics Notes Question 5.
Plastids in the plant cells.
Answer:
Plastids are the cell organelles that are found only in plant cells. They are of 3 types – Chromoplast, Chloroplast and Leucoplast.

Class 8 Science Notes Kerala Syllabus Question 6.
Pigments in the chromoplasts.
Answer:
The pigments in Chromoplast are Xanthophyll (yellow), Carotene (yellowish Orange), Anthocyanin (Red, Purple) etc.

Kerala Syllabus 8th Standard Biology Notes Malayalam Medium Question 7.
Chromoplasts and sunlight.
Answer:
Chloroplast performs photosynthesis in the presence of sunlight. As the fruits ripen, the chloroplast in them changes to chromoplasts.

Class 8 Chemistry Chapter 1 Kerala Syllabus Question 8.
Change of colour and taste in fruits
Answer:
In the storage cells, leucoplasts are more. But as the fruit ripens the chlo- roplasts converted to chromoplasts. Starch changes to sugars. This is the reason behind the change in colour and taste when the fruit ripens.

life’s Mysteries in Little Chambers Let us complete the illustration (Text Book Page No: 18)

8th Class Biology Notes Pdf Malayalam Medium Question 1.
Compare the plant cell and the animal cell and complete the illustration given below.

Answer:

life’s Mysteries in Little Chambers Let us assess (Text Book Page No: 19)

Hsslive Guru 8th Class Biology Kerala Syllabus Question 1.
Complete the concept map related to the structure of animal cells.

Answer:

Std 8 Biology Notes Malayalam Medium Question 2.

(i) Identify the parts A,B, C,D,E marked in the plant cell.
Answer:
A – Chloroplast
B – Mitochondrion
C – Ribosome
D – Vacuole
E – Nucleus

(ii) Write the function of the parts denoted by the letters given below.
Answer:
A – Photosynthesis
B – Production, Storage and distribution of energy
C – Protein synthesis

(iii) In which part of the cell are genes found?
Answer:
Genes are seen in the chromatin reticulum in the nucleus.

life’s Mysteries in Little Chambers Additional Questions and Answers

Basic Science Class 8 Solutions Kerala Syllabus Question 1.
Find the odd one in each group. Also write the common characteristics of the others.
a. Bacteria, Cyanobacteria, Amoeba, Mycoplasma,
b. Golgi complex, Ribosome, Lysosome, Mitochondrion
c. Mitochondrion, Cell membrane, Ribosome, Golgi complex
d. Xanthophyll, Anthocyanin, Tonoplast, Carotene
Answer:
a. Amoeba; The others are prokary otes.
b. Lysosome; The others are present in both plant and animal cell.
c. Cell Membrane; Others are cell organelles

Kerala Syllabus 8th Standard Basic Science Textbook Solutions Question 2.
Find out the relation between the given word pairs and on that basis fill in the blanks.
a. M.J. Schleiden- ………… ; Theodor Schwann- Animal cell
b. Power house – Mitochondrion; Skeleton of cell- …………
c. Bacteria – ………… ; Amoeba – Eukaryote
d. Robert Hooke – Cell; ………… – Nucleus
e. Yellowish orange colour – Ca-rotene; Yellow colour – …………
f. Powerhouse of the cell – Mitochondrion; Transport of materials – …………
Answer:
a. Plant Cell
b. Endoplasmic reticulum
c. Prokaryote
d. Robert Brown
e. Xanthophyll
f. Endoplasmic reticulum

Basic Science Class 8 Chapter 1 Question Answer Question 3.
Copy the given figure, then identify and mark those parts, their features are given.|

a. Cytoskeleton
b. Controll various process inside a cell
c. Power house of cell
Answer:
a. Endoplasmic reticulum – understand, marking
b. Nucleus – understand, marking
c. Mitochondrion – understand, marking

Question 4.
It was Rudolf Virchow who dis-covered one of the prominent characteristics of cell. Analyse the statement.
Answer:
He found the process cell division. New cells are formed only from existing cell.

Question 5.
Which components of plant cell are not found in animal cell?
Answer:
Centrosome, Lysosome.

Question 6.
Some components of Animal cell are also found in the plant cell. List out them.
Answer:
Cell wall, large vacuole, plastids.

Question 7.
What change occur when a mango ripens? What are the causes?
Answer:
Colour changes.
Chloroplast is changed into chromoplast.
The sour taste is changed sweet taste. Starch is changed into sugar.

Question 8.
Choose the parts of microscope from the following terms.

Diaphragm, test tube, objective lens, eye piece, mirror, hammer, watch glass, cover glass, knobs, stage, clip

Answer:
Diaphragm, objective lens, eye piece, mirror, Knobs, Stage, Clip

Question 9.
Make a table showing the different parts of microscope and their function.
Answer:
Eye piece – helps to magnify objects; helps to observe objects
Knobs – to adjust the position of lens
Objective lens – helps to magnify objects
Stage & Clip – object is placed on the stage and the slide is fixed using clips
Diaphragm – helps to reduce the intensity of light Mirror – reflects sunlight

Question 10.
Why does mirror is fixed in the microscope?
Answer:
To allow sunlight on to the material observed.

Question 11.
Why a glass slide is used to place the material to be observed?
Answer:
A transparent surface is needed to fall sunlight reflected by the mirror on the material to be observed.

Question 12.
Why plane mirror and concave mirror are used in the microscope?
Answer:
Plane mirror reflects sunlight.
Concave mirror reflects artificial light.

Question 13.
Ananthu noted the markings 10x and 45x in the objective lens of the microscope. He also noted the markings on the eyepiece too. But he couldn’t understand this? Can you help him?
Answer:
These markings (10x, 45x) denote their magnification power.

Question 14.
How can we find out the magni-fication power of microscope?
Answer:
The product of the numbers seen in the objective lens and eyepiece de-notes its magnification power.

Question 15.
What is the difference between simple microscope and compound microscope?
Answer:
In simple microscope there is only one lens. But in compound micro-scope there are more than one lens.

Question 16.
Why the sections of plantain roots are put in the water taken in the petridish?
Answer:
To avoid dehydration of roots.

Question 17.
Anagha and Priya placed the sections of plantain root on glass slides. After sometime the materials on Anagha’s slide dried up. But Priya’s slide was suitable for observation. What may he the reason for this?
Answer:
To avoid drying up it is needed to add a few drops of glycerine on slide. Priya has done it.

Question 18.
Write procedure for observation of the section of plantain root.
Aim – to observe the cells in the roots of plantain.
Materials required -Plantain root, Petridish, Blade, Brush, Glass slide, Cover slip, Stain, Glycerine, Water, Microscope.
Procedure: –
Answer:

• Take thin sections of the roots of plantain. Put it in the water in a petridish.
• Transfer the sections to the water taken in a watch glass using a brush.
• Put the thinnest and complete sections in a watch glass containing stain.
• Add a few drops of glycerine on slide to avoid dehydration.
• Place the stained section on the slide after putting it in fresh water.
• Cover it using a cover glass to avoid air bubble.
• Wipe out the excess glycerine using a tissue paper.

Question 19.
Match the Scientists and their contributions.
Rudolf Virchow – a. Found out that plant body is made up of cells.
M. J. Schleiden – b. Observed cells for the first time.
Robert Hooke – c. Found out that animal body is formed of cells.
Robert Brown – d. Formulated the inference that new cells form only from the existing ones.
Theodor Schwann – e.Invented nucleus.
Answer:
Rudolf Virchow – b
M. J. Schleiden – a
Robert Hooke – b
Robert Brown – e
Theodor Schwann – c

Question 20.
State Cell theory
Answer:
All living body is formed of cells. Cells are the structural and functional units of organisms.

Question 21.
Who are the founders of Cell Theory?
Answer:
MJ. Schleiden and Theodor Schwann.

Question 22.
“Our body is composed of millions of cells. Why these much of cells?” – Ananthu
‘They have various functions to perform’ – Bhadra
List out the functions of cells in the body.
Answer:

1. Defend foreign particles.
2. Releases energy from the cells.
3. Synthesis biomolecules.

Question 23.
Classify the given cell organelles under suitable headings. Common terms can be included in both groups.
Ribosome, Nucleus, Cell membrane,Centrosome, Chloroplast, Vacuole, Golgi Complex, Mitochondrion, Lysosome
Answer:

Plant cell	Animal cell
Cell wall	Centrosome
Chloroplast	Lysosome
Vacuole	Ribosome
Ribosome	Nucleus
Nucleus	Golgi complex
Golgi Complex	Mitochondrion
Mitochondrion	Cell membrane
Cell membrane

Question 24.
Identify the cell organelles that perform the functions mentioned below.

1. Encloses enzymes, hormones etc in small vesicles
2. Gives strength and shape to cells.
3. Power house of the cell.

Answer:

1. b. Golgi complex
2. c. Endoplasmic reticulum
3. a. Mitochondrion

Question 25.
Complete the labelling of the given diagram of plant cell suitably.

Answer:
a. Nucleus
b. Centre of protein synthesis in the cell
c. Mitochondrion
d. Power house of the cell

Question 26.
Complete the illustration given below.
Vacuole, Mitochondrion, Endoplasmic Reticulum, Golgi complex

Answer:
Vacuole – Stores water, salts, and waste materials.

Mitochondrion – Power house of the cell, helps in the production and storage of energy.

Endoplasmic Reticulum – Pathway inside the cell. Provide rigidity and shape to cells.

Golgi Complex – Encloses enzymes, hormones & mucus in small vesicles.

Question 27.
While discussing about the cell Kunchu has a doubt” Are Protoplasm and Cytoplasm one and the same?” What is your response?
Answer:
Protoplasm constitutes all materials within the cell membrane. Cytoplasm is the part of protoplasm except the nucleus.

Question 28.
What is the difference between simple microscopes and electron microscopes?
Answer:
Simple Microscope

• Magnifies an object 2000 times its actual size
• Light source is used to see objects Electron Microscope
• Magnifies objects million times
• Electrons are utilized instead of light source.

Question 29.
Complete the table showing dif-ferent parts of nucleus and their functions.
Answer:

Question 30.
“Can organisms live without a definite nucleus”? I can’t believe it. Have you noticed Gopika’s doubt? How will you clarity this doubt?
Answer:
There are certain organisms without a definite nucleus. In bacteria, cyanobacteria and mycoplasma, there is no nucleus. They are called prokaryotes.

But in the cells of Amoeba, animals and plants there is a well defined nucleus covered with membrane. These are known as eukaryotes.

Question 31.
Complete the given flow chart.

Answer:
a – Chloroplast
b – Leucoplast
c – Imparts colour to fruits and flowers.

Question 32.
Why do the cell membranes called selectively permeable membranes?
Answer:
Hence they allow only the essential materials to pass through.

Question 33.
How does the colour of fruits change when they ripen?
Answer:
As fruits ripens, the chloroplasts get converted to chromoplasts. Thus colour changes.

Question 34.
Describe the function of Centrosomes.
Answer:
Centrosomes is the cell organelle that is found only in animal cells. The centrioles that play a major role in cell division. It helps to the formation of spindle fibers.

Question 35.
Find out statements which are relate to animal cells from the following statements.
• seen cell wall.
• seen cell membrane.
• seen mitochondrion.
• seen vacuole and chloroplast.
Answer:
• seen cell membrane.
• seen mitochondrion.

Question 36.
How spindle fibres are formed in plant cells and fungus cells?
Answer:
In plant cells and fungus cells spindle fibres are formed through microtubule organising centre.

Question 37.
Why are biomembranes known as selectively permeable membrane?
Answer:
The exchange of materials between cells and between cell organelles and cytoplasm occurs through biomembranes. These membranes do not allow all but some materials to pass. Hence they are selectively permeable membrane.

Question 38.
The discovery of electron microscope enables the detailed study on the cells easy. How?
Answer:
The electron microscope can magnify an object into millions of time of the original size. So it helps to understand more about the micro structures of the cell.

Question 39.
What are unicellular organisms? Write examples for this?
Answer:
Some organisms have only a single cell in their body. Such organisms are called unicellular organisms,
eg: Amoeba, Paramoecium and Euglena.

Question 40.
What are multicellular organisms?
Answer:
There are a number of cells in the body of these creatures. They are therefore know as multicejlular organisms.

Question 41.
What is cell wall?
Answer:
Cell wall is the covering seen outer to the plasma membrane in plants. It is composed of cellulose. It has numerous pores. Movement of molecules is possible through these pores.

Question 42.
How do animal cells differ from the plant cells in structure?
Answer:
Plant cell and animal cell are often structurally same. But the plant cell is surrounded by a rigid protective cell wall formed of cellulose. Cell wall is the major factor by which we can identify the animal cells from plant cells. In plant cell large vacuole and chloroplasts are seen.

Question 43.
Draw the diagrammatic repres-entation of animal cells and plant cells and illustrate the parts?
Answer:
Animal cell

Plant cell

You can Download Equal Triangles Questions and Answers, Activity, Notes, Kerala Syllabus 8th Standard Maths Solutions Chapter 10 help you to revise complete Syllabus and score more marks in your examinations.

Kerala State Syllabus 8th Standard Maths Solutions Chapter 10 Statistics

Statistics Text Book Questions and Answers

Textbook Page No 184

Class 8 Maths Chapter Statistics Kerala Syllabus Question 1.
The number of members in 50 households of a village are listed below.

Make a frequency table and answer these questions:
i. How many households have just two members?
ii. How many households have four or less?
iii. How many households have ten or more?
iv. Households of what size occurs the most?
Solution:

i. 5
ii. 5 + 11 + 9 = 25
iii. 1 + 1 = 2
iv. 3

8th Standard Maths Statistics Kerala Syllabus Question 2.
There are 44 children in class 8B. The list shows how far they come from, in kilometres.

Make a frequency table and answer these questions:
i. How many children are from exactly 1 kilometre away?
ii. How many are from more than 5 kilometres?
iii. How many are from between 5 and 10 kilometres?
iv. How many are from more than 10 kilometres?
Solution:

i. 3
ii. 21
iii. 23
iv. 4

8th Standard Maths Guide Kerala Syllabus  Question 3.
The scores of 35 children in a test are given below:

Make a frequency table and answers these questions:
i. How many children scored 20?
ii. How many children got scores between 10 and 20?
iii. How many scored less than 10?
iv. What is the score most number of children got?
Solution:
Score Tally Number of children

i. 1
ii. 32
iii. 0
iv. 15

Textbook Page No 188

Statistics Class 8 Notes Kerala Syllabus Question 4.
Given below are the highest temperatures (in degree Celsius) one day in 40 towns. Make a frequency table.

Solution:

8th Class Maths Statistics Kerala Syllabus Question 5.
The heights (in centimeters) of 45 people who look part in a physical fitness test are given below? Make a frequency table.

Solution:

Textbook Page No 190

Hss Live Guru Maths 8th Kerala Syllabus Question 6.
The table shows the times 30 children took to complete a long distance race. Draw a histogram of this.

Solution:

Hsslive Guru Maths 8th Standard Kerala Syllabus Question 7.
The table shows the daily incomes of 6o households in a locality.

Draw a histogram.
Solution:

Hss Live Std 8 Maths Kerala Syllabus Question 8.
Detail of rainfall in June and July are given in the table below. Draw a histogram.

Solution:

Hsslive Guru 8th Class Maths Kerala Syllabus Question 9.
The time taken by 25 women and 23 men to complete a race are given in the table below. Draw separate histograms for men and women.

Solution:

Kerala Syllabus 8th Standard Maths Notes Question 10.
The weights of 45 children in a class are listed below.


Make a frequency table and draw a histogram.
Solution:

Additional Questions And Answers

8th Standard Maths Kerala Syllabus Question 1.
Complete the table below on the basis of the histogram.

Solution:

8th Class Maths Notes Kerala Syllabus Question 2.
Teacher conducted a test in her class of 45 students. Their score out of a total of 10 are given below.

a. Construct a frequency table representing these details?
b. Construct a bar graph?
Solution:

Hss Live Guru Class 8 Maths Kerala Syllabus Question 3.
The list below gives the daily wages earned by 30 laboures. Prepare a frequency table of these.

a. What is the daily wages of most labourers?
b. How many get 250 rupees a day?
c. How many get the least amount of wages?
Solution:

a. 225
b. 6
c. 5

Class 8 Maths Chapter 10 Kerala Syllabus Question 4.
The table shows daily expenditure of 60 household in a locality. Draw histrogram.

Solution:

8th Standard Maths Notes Kerala Syllabus Question 5.
Given below are the amount of rainfall (in mm) one day in 61 towns. Make a frequency table.


Solution:

8th Std Maths Solution Guide Kerala Syllabus Question 6.
The runs that a batsman got in 40 one – day cricket matches are given below. Make a frequency table and answer these questions.

a. How many centuries did he get?
b. How many half centimes?
c. In how many games did he score less than 50?
Solution:

Question 7.
The height of 30 childrens in a class are listed below. Mark a frequency table and draw a histogram.

Solution:

Students can Download Maths Chapter 3 Polygons Questions and Answers, Notes Pdf, Activity in Malayalam Medium, Kerala Syllabus 8th Standard Maths Solutions helps you to revise the complete Kerala State Syllabus and score more marks in your examinations.

Kerala State Syllabus 8th Standard Maths Solutions Chapter 3 Polygons in Malayalam

Polygons Text Book Questions and Answers

You can Download मेरे बच्चे को सिखाएँ Questions and Answers, Summary, Activity, Notes, Kerala Syllabus 8th Standard Hindi Solutions Unit 2 Chapter 3 help you to revise complete Syllabus and score more marks in your examinations.

Kerala State Syllabus 8th Standard Hindi Solutions Unit 2 Chapter 3 मेरे बच्चे को सिखाएँ (पत्र)

मेरे बच्चे को सिखाएँ पाठ्यपुस्तक के प्रश्न और उत्तर

Mere Bache Ko Sikhaye Notes 8th Kerala Syllabus प्रश्ना 1.
“मेहनत से कमाया एक पैसा भी, हराम में मिली नोटों की गड्डी से कहीं अधिक मूल्यवान होता है।” अपना दृष्टिकोण प्रकट करें।

उत्तर:
यह कथन बिलकुल ठीक है। हराम की चीजें हमारे हक का नहीं है। मेहनत से कमाया पैसा ही मूल्यवान है। मानव को ईमानदारी के साथ जीना है। मेहनत ईमानदारी में चार चाँद लगाता है।

Kerala Syllabus 8th Standard Hindi Notes प्रश्ना 2.
‘बदमाशों को आसानी से काबू में किया जा सकता है। ऐसा क्यों कहा होगा?

उत्तर:
बदमाशों के अंदर भी कुछ सच्चाई होती है। उपदेश और सत्संग के द्वारा उन सच्चाइयों को बाहर ला सकते हैं। इसलिए ऐसा कहा गया है।

Hindi State Syllabus 8th Standard प्रश्ना 3.
‘नकल करके पास होने से फेल होना बेहतर है’ इस प्रस्ताव से क्या आप सहमत है? क्यों?

उत्तर:
मैं इससे शतप्रतिशत सहमत हूँ। नकल से मिली जीत में ज्ञान की गहराई नहीं होती। यह तत्काल लाभ दे सकता है। लेकिन भविष्य में इससे कोई मुनाफ़ा नहीं होता। इसलिए फेल से सीख लेना ही बेहतर है।

8th Standard Hindi Guide Kerala Syllabus प्रश्ना 4.
‘भीड़ से अलग होकर अपना रास्ता बनाना’ का मतलब क्या है?

उत्तर:
भीड़ एक ही मानसिकता के आधार पर चलती है। भीड़ की मानसिकता से अलग होकर सोचने से ही नई दृष्टि और नए विचार मिलते हैं। इस नए दृष्टिकोण से ही सामाजिक प्रगति संभव होती है। संसार के सभी महत् व्यक्ति इस प्रकार सोचनेवाले थे। इसलिए उन्हें संसार में बदलाव ला सका।

मेरे बच्चे को सिखाएँ Textbook Activities

8th Standard Hindi Notes State Syllabus प्रश्ना 1.
लघु-लेख लिखें।
‘सफल जीवन’ विषय पर लघु-लेख लिखें।

उत्तर:
सफल जीवन
जीवन को सफल बनाने के लिए मनुष्य को आत्मविश्वास, दृढ़संकल्प, अदम्य उत्साह और लगन चाहिए। केवल पढ़ने से ही नहीं, अच्छे चरित्र के निर्माण में भी मानव को ध्यान देना चाहिए। उसे परिश्रमी होना चाहिए। उसे यह समझना चाहिए कि नुशासन जीवन को सफल और उज्ज्वल बनाने के लिए आवश्यक है। व्यक्ति को सादा जीवन और उच्च विचार का आदर्श ग्रहण करना चाहिए। उसे बुरी आदतों और बुरे सहवास से बचकर रहना भी होगा। अपने पाठों को लगन से पढ़ना, बड़ों के सदुपदेशों का पालन करना, बड़ों से आदर और छोटों से प्यार करना आदि की आवश्यकता है। उसे पथभ्रष्ट करनेवाली बातों से बचकर रहना भी चाहिए। जो व्यक्ति इस प्रकार का जीवन बिताएगा, वह अपने जीवन में सफल बनेगा।

मेरे बच्चे को सिखाएँ मेरी रचना में

उचित चौकार में ✓ लगाएं।


विषय का विश्लेषण किया है।

प्रस्तुतीकरण में क्रमबद्धता है।

उचित भाषा का प्रयोग किया है।

अपना दृष्टिकोण प्रस्तुत किया है।

उचित शीर्षक दिया है।

मेरे बच्चे को सिखाएँ Summary in Malayalam and Translation

मेरे बच्चे को सिखाएँ शब्दार्थ Word meanings

You can Download दोहे Questions and Answers, Summary, Activity, Notes, Kerala Syllabus 8th Standard Hindi Solutions Unit 3 Chapter 3 help you to revise complete Syllabus and score more marks in your examinations.

Kerala State Syllabus 8th Standard Hindi Solutions Unit 3 Chapter 3 दोहे (कविता)

दोहे Summary in Malayalam and Translation

बड़ा हुआ तो क्या हुआ, जैसे पेड़ खजूर।
पंथी को छाया नाहिं, फल लागै अतिदूर।।

Kabir Ke Dohe Hindi Poem 8th Standard भावार्थ :
इस दोहे में कबीरदास कहते हैं कि खजूर के पड़ के समान बडा होने से कोई फायदा नहीं है। बहुत लंबा होने के कारण पथिक को छाया नहीं मिलती है। फल भी बहुत ऊँचाई पर लगते हैं। वह भी लोगों केलिए अप्राप्य है। मतलब है कि हम बड़े होकर भी दूसरों को कोई उपकार नहीं करते तो उस बडप्पन से किसी को कोई लाभ नहीं। दूसरों की भलाई करनेवाले ही सच्चे अर्थ में बडे होते हैं।

रहीम वे नर धन्य हैं, पर उपकारी अंग।
बाँटन पारे को लगे, ज्यों मेहंदी को रंग।।

8th Class Hindi Dohe Kerala Syllabus भावार्थ :
रहीस कहते हैं – वे नर धन्य है जिनका शरीर सदा सबका उपकार है। जिसप्रकार मेहंदी बाँटनेवाले के अंग पर भी मेहंदी का रंग लगा जाता है उसी प्रकार परोपकारी का शरीर भी सुशोभित होता है। .

Rahim Ke Dohe Question Answer Kerala Syllabus दोहे शब्दार्थ Word meanings

You can Download जल-बैंक Questions and Answers, Summary, Activity, Notes, Kerala Syllabus 8th Standard Hindi Solutions Unit 4 Chapter 3 help you to revise complete Syllabus and score more marks in your examinations.

Kerala State Syllabus 8th Standard Hindi Solutions Unit 4 Chapter 3 जल-बैंक

जल-बैंक पाठ्यपुस्तक के प्रश्न और उत्तर

Jal Bank Hindi Story Kerala Syllabus 8th प्रश्ना 1.
‘चप्पे-चप्पे पर जल बैंक खुल गए हैं।’ लेखक की इस कल्पना के पीछे भविष्य का कौन-सा संकेत है?

उत्तर:
पानी की कमी एक गंभीर समस्या बनती जा रही है। अब भी हम इस दिशा पर ध्यान न रखेंगे तो भविष्य बड़ी आपत्ति हो जाएगी। पानी के लिए हमें किसी जल बैंक जैसी व्यवस्थाओं का आश्रय लेना पड़ेगा।

Hss Live Guru 8 Hindi Kerala Syllabus प्रश्ना 2.
‘पानी-पानी होना’, ‘पानीदार होना’ आदि प्रयोगों का मतलब क्या है?

उत्तर:
‘पानी-पानी होना’ का मतलब है- अत्यंत लज्जित होना और ‘पानीदार होना’ का मतलब होना- धनी होना।

Hss Live Guru Hindi 8th Kerala Syllabus प्रश्ना 3.
‘घर में पीने के वास्ते भी एक बूंद नहीं है’ लोग ऐसा झूठ क्यों कहते हैं?

उत्तर:
पानी की कमी बहुत है। लेकिन कुछ लोग उसके उपयोग में सावधानी नहीं बरते। कुछ लोग पानी के बिना तरसते हैं। उनके सामने लोग झूठ बोलते हैं कि पीने के लिए भी एक बूंद पानी नहीं है। यहाँ लोगों की संकुचित भाव की ओर संकेत है।

Hss Live Guru 8th Hindi Kerala Syllabus प्रश्ना 4.
‘चारों उँगलियाँ पानी में’ इस प्रयोग से आप क्या समझते हैं?

उत्तर:
‘चारों उँगलियाँ पानी में’ का मतलब है- जीवन में बड़ा नुकसान होना।

जल-बैंक Textbook Activities

Hsslive Guru Hindi Class 8 Kerala Syllabus प्रश्ना 1.
चर्चा करें।
जल बैंक की संकल्पना कैसी लगी?
वर्तमान समाज में इसकी प्रासंगिकता क्या है?

उत्तर:
जल दुर्लभता आज की विकट समस्या है। ऐसी स्थिति में जलबैंक की संकल्पना उचित है।

Hsslive Guru 8th Hindi Kerala Syllabus प्रश्ना 2.
जल-संरक्षण की आवश्यकता पर नारे बनाएँ।

जल है तो कल है।
जल जीवन का आधार।
जल नहीं तो हम नहीं।
जल ही जीवन है।
बूंद-बूंद का संरक्षण, जीवन का संरक्षण।
आज संजोएँ हरेक बूंद, कल को बनाएँ खूब सुहाना।

Hsslive Guru 8th Class Hindi Kerala Syllabus प्रश्ना 3.
उपर्युक्त नारों की मदद से पोस्टर तैयार करें।

जल-बैंक Summary in Malayalam and Translation

 जल-बैंक शब्दार्थ Word meanings

You can Download Basic Constituents of Matter Questions and Answers, Summary, Activity, Notes, Kerala Syllabus 8th Standard Basic Science Solutions Chapter 5 help you to revise complete Syllabus and score more marks in your examinations.

Kerala State Syllabus 8th Standard Basic Science Solutions Chapter 5 Basic Constituents of Matter

Basic Constituents of Matter Questions and Answers

The particles in sugar candy and potassium permanganate solutions cannot be seen as they are extremely small. If we take one or two pieces of camphor in a china dish and heat the china dish. Even though the camphor has disappeared completely, the smell of camphor remains in air. This is because the camphor has spread in air as extremely small particles.

Fill one quarter of a boiling tube with sugar and close it with cotton. Then heat the boiling tube strongly. The water in sugar is sticked on the sides of the boiling tube as water vapour. Carbon and water are the components of sugar. Water can be further divided. When electricity is passed through water it splits into hydrogen and oxygen. That is sugar, a pure substance, can be divided into carbon, hydrogen, and oxygen. At the same time, pure substances like carbon, hydrogen, oxygen, gold, and silver cannot be further divided into its components by chemical reactions.

Basic Constituents Of Matter Class 8 Kerala Syllabus Elements and Compounds

The pure substances which cannot be further decomposed through chemical processes are called elements.
Ex: hydrogen, oxygen, gold, silver Compounds are pure substances formed from two or more elements through chemical combination.
Ex : water, sugar, carbon dioxide

Origin of the names of elements

In the past, the elements were named after places, countries, continents, characteristic properties, scientists, planets, satellite etc.
Ex : Place – polonium, francium
Continent – Europium, Americium
Character, colour – rubedium, chromium
Scientist – bohrium, curium
Planet – neptunium

Basic Constituents Of Matter Class 8 Questions And Answers Kerala Syllabus Symbols

The first letter of the English or latin letters are used as the symbols of the ele-ments.
Ex: Carbon – C
Oxygen – O
Sodium-Natrium – Na
Potassium-Kalium – K
But, for some elements, along with the first letter, the second or another prominent letter is also used in the symbol as a small letter.
Ex: Calcium – Ca
Chlorine – Cl

Basic Constituents Of Matter Class 8 Notes Pdf Kerala Syllabus Atom and Molecule

The element carbon is made up of extremely small particles. Think of breaking a piece of carbon into smaller and smaller particles. When it is broken up in this manner, we get the smallest particle which retains all the characteristic properties of carbon at the end. This smallest particle is called an atom of carbon.

Atoms of some gaseous elements like helium, neon etc., can exist as free single atoms. But atoms of some other gaseous elements like hydrogen, oxygen etc., can exist only as a combination of two atoms. Atoms of some elements are seen to exist as a combination of more than two atoms. The smallest particles which can exist independently are called molecules.

Method of representing Atoms and Molecules

The symbol of helium is ‘He’. When we write ‘He’, it represents one atom of the element helium. 2He means two helium atoms.

Elements like helium, neon, argon, etc., are seen in nature as single atoms. But elements like hydrogen exist as diatomic molecules. Hydrogen atom is represented as H. But H₂ represents a hydrogen molecule.

Some elements exist as molecules of more than two atoms. Phosphorus (P₄), sulphur (S₈), etc., are examples of such
elements.

Molecules with only one atom are called monatomic molecules.
Ex: He, Na

Those with two atoms each are called diatomic molecules.
Eg: O₂, H₂, N₂

The molecules with more than two atoms are called polyatomic molecules.
Eg: P₄ S₈

In monatomic molecules, the number given on the left side of the symbol indicates the number of molecules and atoms. In polyatomic molecules, the subscript on the right side of the symbol indicates the number of atoms within one molecule. The total number of molecules is indicated on the left side.
O – One oxygen atom
O₂– One oxygen molecule
2O₂ – Two oxygen molecules
2He – Two helium atom/molecule
5Na – five sodium atoms

Basic Constituents Of Matter Kerala Syllabus  Compounds

We have seen how molecules are formed from the same type of atoms. Similarly, the compounds contain molecules formed from atoms of different elements.

Carbon dioxide molecule is formed when one carbon atom combines with one oxygen atom.

This is a compound. Water is a compound formed by the combination of hydrogen and oxygen.

Carbon dioxide is formed when carbon burns in oxygen. Carbon dioxide is also formed by the decomposition of calcium carbonate. Whatever be the sourcj of a compound, a fixed ratio is maintained between the atoms of the different elements present in it. In carbon dioxide molecule, the ratio of carbon atoms to oxygen atoms is always 1: 2. Thus carbon dioxide molecule can be represented as CO₂. Similarly in water molecule the ratio of hydrogen and oxygen atom is 2:1 This type of representation is known as the chemical formula of the compound.
H₂SO₄ ,CO₂ ,H₂O, HCl, NaCl

2CO₂ represents two carbondioxide molecules. We can understand that there are 6 atoms including 2 carbon atoms and 4 oxygen atoms in 2CO₂.

There are 7 atoms including 2 hydrogen atoms, 1 sulphur atom and 4 oxygen atoms in H₂ SO₄, Molecule. There will be 14 atoms in 2H₂ SO₄

Basic Constituents Of Matter Notes Kerala Syllabus Chemical Equations

The chemical equation of the reaction between zinc and hydrochloric acid forming zinc chloride and hydrogen is written as shown below.
Zn+HCl → ZnCl₂ + H₂

Here Zn and HCl are reactants. ZnCl₂ and H₂ are products.

The chemical reactions can be represented as equations containing the symbols and chemical formulae of the reacta¬nts and the products. When a chemical equation is written, the number of atoms of the same kind, on the side of reactants and that of products should be equal. That is the chemical equation given above is to be rewrite as
Zn + 2 HCl → ZnCl₂ + H₂

Now the number of atoms in both side of the arrow is equal. This type of chemical equations which is written such that the number of atoms of same type is equal in the side of reactants and products are called balanced chemical equations.

Basic Constituents of Matter Textbook Questions and Answers

Basic Science Class 8 Chapter 5 Kerala Syllabus Question 1.
Classify the following into elements and compounds. Ammonia, sugar, nitrogen, mercury, sodium chloride, water, copper sulphate, sodium, carbon.
Answe:

Elements	Compounds
Mercury	Ammonia
Sodium	Sugar
Carbon	Sodium chloride
Nitrogen	Water
	Copper sulphate

Hsslive Guru 8th Class Chemistry Kerala Syllabus Question 2.
Analyse the chemical equation given for the reaction between nitrogen and hydrogen to give ammonia.
N₂+3H₂ → 2NH₃
a. What are the reactants and products in this reaction?
b. Find the total number of molecules and atoms of the reactants.
c. Find the total number of molecules and atoms of the products.
d. What is the relation between the number of atoms of the reactants and products?
Answer:
a. Reactants: nitrogen, hydrogen Product: ammonia (NH₃)
b. Total number of molecules in reactant – 4 total atoms- 8
c. Total number of molecules in product -2 total atoms- 8
d. Total number of atoms in reactants and products are equal.

Hsslive Guru Chemistry 8 Kerala Syllabus Question 3.
N is the symbol of nitrogen.
a. What do N₂, 2N and 2N₂ indicate?
b. How many molecules and atoms are present in 5N₂?
Answer:
a. N₂ – One nitrogen molecule
2N – Two nitrogen atoms
2N₂ – Two nitrogen molecules
b. 5N₂ – 10 atoms, 5 molecules

Hss Live Guru 8th Chemistry Kerala Syllabus Question 4.
Some chemical equations are given.
C + O₂ → CO₂
CH₄ + 2O₂ → CO₂ + 2H₂O
N₂ + O₂ → NO
CaCO₃ → CaO + CO₂
H₂ + I₂ → HI
Fe + HCl → FeCl₂ + H₂
CO₂ + C → CO
a. Which of these are balanced chemical equations?
b. Balance those equations which are not balanced.
Answer:
a. C + O₂ → CO₂
CH₄ + 2O₂ → CO₂ + 2H₂O
CaCO₃ → CaO + CO₂

b. N₂ + O₂ → 2NO
H₂ + I₂ → 2Hl
Fe + HCl → FeCl₂ + H₂
CO₂ + C → 2CO

Basic Science Class 8 Solutions Kerala Syllabus Question 5.
Find whether the following statements are right or wrong.
a. All atoms of the same element show the same properties.
b. The atoms present in a compound are different.
c. Elements are pure substances.
d. Hydrogen is a monatomic molecule
Answer:
a. True
b. True
c. True
d. False

Matter And Chemical Formula Class 7 Kerala Syllabus Question 6.
Take iron powder and sulphur powder in their mass ratio of 7:4 in a china dish. Heat it strongly for some time.
a. Try to separate the iron powder using a magnet. What can be observed? What is the reason?
b. Add a .little dilute hydrochloric acid to the above product; observe the changes taking place, and write them down.
c. Write down the inferences you have arrived at from these observations.
Answer:
Sulphur is reacted with iron powder to form ferrous sulphide therefore it cannot be separated.
There will be the smell of rotten egg because hydrogen sulphide is produced.

8th Class Chemistry State Syllabus Kerala Syllabus Question 7.
Make and exhibit the models of the following molecules using ball and sticks, different fruits and splints.
a. Water (H₂O)
b. Ammonia (NH₃)
c. Carbon dioxide (CO₂)
d. Methane (CH₄)
Answer:
Do your self

Basic Science Class 8 Pdf Notes Kerala Syllabus Question 8.
Haven’t you understood how symbols are assigned to elements? Given below are some elements that received symbols from their Latin names. Complete the table with the help of the Periodic Table.

 

Element	Latin name	Symbol
Silver	……………..	……………..
……………..	Hydrargium	……………..
Tin	……………..	……………..
……………..	……………..	Pb
Antimony	……………..	……………..
……………..	Aurum	……………..

Answer:

Element	Latin name	Svmbol
Silver	Arguntum	Ag
Mercury	Hydrargium	Hg
Tin	Stannum	Sn
Lead	Plumbum	Pb
Antimony	Stibium	Sb
Gold	Aurum	Au

Basic Constituents of Matter Additional Questions and Answers

Basic Science Question Answer Chapter Wise Class 8 Kerala Syllabus Question 1.
Choose the correct symbol of the elements given below from the box.
(Calcium, carbon, sodium, potassium, Iron, silver)
(S, C, Na, Ca, Si, Ag, In, P, K, Fe)
Answer:
Calcium-Ca,
Carbon-C,
Sodium- Na,
Potassium- K,
Iron- Fe,
Silver- Ag

Basic Science For Class 8 Chapter 5 Kerala Syllabus Question 2.
The chemical formula of calcium bisulphate is Ca (HSO₄)₂. Write down the number of atoms of each element present in this molecule.
Answer:
Ca=1, H=2, S=2, 0=8

Basic Science Class 8 Kerala Syllabus Question 3.
Na. This is the symbol of an element. Which statement given below is wrong. Justify?

• Symbol of Nitrogen
• Indicates one atom.

Answer:
Symbol of Nitrogen.
The symbol that represent the element Nitrogen is ‘N’. ‘Na’ is the symbol of sodium.

8th Class Chemistry Notes Pdf Kerala Syllabus Question 4.
We know about elements and compounds. Find out the odd one from the following. Give reason?
a. (A) Hydrogen (B) Oxygen (C)Nitrogen (D) Carbon dioxide
b. (A) Sodium (Na), (B) Pottasium (K) (C) Magnesium (Mg), (D) Iron (Fe)
c. Write the molecular formula of carbon dioxide?
d. What is the Latin name of sodium?
Answer:
a. Carbon dioxide – Compound, others are elements.
b. Magnesium – Others take symbols from their Latin name.
c. CO₂
d. Natrium

8th Std Basic Science Textbook Kerala Syllabus Question 5.
Arrange the following from smallest to largest.

Answer:
Atom → Molecule → Small particle → Substances

Physics Class 8 Kerala Syllabus Question 6.
Represent the basis of nomenclature of elements given in the following table.
a.

Element	Basis of nomenc­lature
Francium Rutherfordium

b. Which element symbol is Cl?
c. What are the constitute elements containing of CaF₂ molecule?
Answer:
a. Name of country
b. Name of scientist
c. Chlorine
d. Calcium, -Fluorine

Question 7.
Symbol of Nitrogen is ‘N’.
a. What represent symbols of 2N and N₂?
b. How many atoms are in 2NH₃?
c. How can represent 5 water molecules?
Answer:
a. 2N represent 2 atoms of Nftrogen. N₂ represent Nitrogen molecules can be formed by combining two atoms of Nitrogen.
b. 8 atoms
c. 5 H₂O

Question 8.
Evaluate the given chemical equation and answer the following questions.
SO₂ + O₂ – SO₃
a. Which are the reactants in the chemical reaction?
b. What is the product of the chemical reaction?
c. Write the balanced chemical equation?
Answer:
a. SO₂, O₂
b. SO₃
c. 2SO₂ + O₂ → 2SO₃

Question 9.
Find the monoatomic molecule from given elements.
a. (A) Hydrogen (B) Oxygen (C)Nitrogen (D) Helium
b. Write the symbols of Hydrogen and Helium?
c. Write chemical formula of Oxygen molecule?
d. What is the Latin name of sodium?
Answer:
a. (D) Helium
b. Hydrogen (H), Helium (He)
c. O
d. Natrium

Question 10.
Select the compounds from the following:
HCl, CO₂, O₂, NaCl, H₂, H₂O, Na, HCl
Answer:
NaCl, CO₂, H₂O, HCl

Question 11.
Form a table of elements which are related to the name of scientists from the following Americum, Mentelivium, Titanium, Rutherfordium, Rubedium, Einstenium, Europeum, Bohrium
Answer:
Mentelivium, Rutherfordium, Einstenium, Bohrium

Question 12.
Examine the following symbols and write the name of elements Ca, Cr, Cl, Be, Na, Fe, Cu
Answer:
Calcium, Chromium, Chlorine, Berelium, Sodium, Iron, Copper

Question 13.
Fill in Blanks suitably
Element – Atom,
Compound – …………
Answer:
Element – Atom,
Compound – Molecule

Question 14.
Complete the following table

Element	Basis of Naming
Americum
Francium
Rubedium
Plutonium
Titanium
Mentalivium
Rutherfordium

Answer:

Element	Basis of Naming
Americum	America- continent
Francium	France – country
Rubedium	Ruby – Colour
Plutonium	Pluto- planet
Titanium	Titan – God
Mentalivium	Mentelief – Scientist
Rutherfordium	Rutherford – Scientist

Question 15.
Examine the following molecules and tabulate the atoms contained in them.
1. Carbon dioxide
2. hydrogen chloride
3. Water
4. sugar
5. Mercuric oxide
Answer:
1. C, O;
2. H, Cl
3- H, O;
4. H, C, O;
5- Hg, 0

Question 16.
Complete the tables

Element	English name	Symbol
Carbon	Carbon	C
Oxygen	………….	………….
………….	Nitrogen	………….
………….	………….	H

Answer:

Element	English name	Symbol
Carbon	Carbon	C
Oxygen	Oxygen	0
Nitrogen	Nitrogen	N
Hydrogen	Hydrogen	H

Question 17.
Tabulate the number of atoms and molecules
5H₂, 2H₂ O, 3ZnCl₂, CO₂
Answer:

Compound	Number of atoms	Number of molecules
5H2	10	5
2H20	6	2
3ZnCl2	9	3
co2	3	1
co2	3	1

Question 18.
Write the diatomic molecules from the following
H₂, Na, C, N₂, P₄, O₂
Answer:
H₂, N₂, O₂

Question 19.
Complete the table

Monatomic	Diatomic	Polyatomic
………..	H2	P4
Na	………..	………..
He	………..	………..

Answer:

Monatomic	Diatomic	Polyatomic
C	H2	P4
Na	O2	O3
Ne	N2	S8
He	Cl2

Question 20.
How many hydrogen and sulphur atoms are there in H₂SO₄ molecule?
Answer:
Hydrogen-2 Sulphar-1

Question 21.
Complete the table.

Substance	No. Of molecules	No. of atoms
P4
02
5Na
2Na
6Cl2
2He

Answer:

Substance	No. Of molecules	No. of atoms
P4	1	4
02	1	2
5Na	5	5
2Na	2	2
6Cl2	6	12
2He	2	2

Question 22.
Find the total number of atoms in the following molecules
a. CO
b. 5 H₂O
c. 7 NH₃
d. 2 Cl₂ H₂₂ O₁₁
e. 3 NaCl
f. ZnCl₂
Answer:
a. CO – 2
b. 5 H₂O -15;
c. 7 NH₃ – 28;
d. 2C₂ H₂₂ O₁₁ – 90
e. 3 NaCl – 6
f. ZnCl₂ – 3

Question 23.
The chemical formula of water is H₂O. Write the ratio of hydrogen and oxygen atoms in water molecule.
Answer:
Ratio of hydrogen and oxygen is 2:1

Question 24.
Tabulate the reactants and products in the following chemical equation.
1. 2H₂ + O₂ → 2H₂O
2. Na + Cl₂ → 2NaCl
3. C + O₂ → CO₂
4. H₂ +Cl₂ → 2HCl
Answer:

Question 25.
Balance the following equations which are not balanced.
C + O₂ → CO₂
H₂ + N₂ → NH₃
Mg + O₂ → Mgo
2H₂ + O₂ → 2H₂O
Answer:
3 H₂ + N₂ → 2NH₃
2Mg+O₂ → 2MgO

Question 26.
How did the symbol system introduced by Berzelius, help the study of chemistry?
Answer:

• The study of chemistry became simple and easy.
• Writing chemical equations representing chemical reactions became very easy.
• The number of atoms in a molecule can be found out from the symbol of the molecule of the element.

Question 27.
Balance the equation
1. NaOH + H₂ SO₄ → Na₂ SO₄ + H₂O
2. H₂O₂ → H₂O + O₂
3. CH₄ + O₂ → CO₂ + H₂O
4. NaOH + HCl → NaCl + H₂O
5. H₂O + CO₂ → C₆H₁₂O₆ + O₂
Answer:
2NaOH + H₂SO₄ → Na₂SO₄ + 2H₂O
2H₂ O₂ → 2HO₂ + O₂
CH₄ +O₂ → CO₂ + 2H₂O
2NaOH + 2HCl → 2NaCl + 2H₂O
6 H₂O + 6CO₂ → C₆ H₁₂ + 6 O₂