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NCERT Solutions for Class 7th Science

 

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Chapter 4. Heat

Additional Questions with Answers

 

 

 

AddiAdditional questions with solutions: (Notes)

Que. – What is thermometer?

Ans. – A device which is used for recording temperature is known as thermometer.

Que. – What is clinical thermometer?

Ans. - A device which is used for recording body temperature is known as clinical thermometer.

Que. – What is the temperature of normal body?

Ans. – 37 °C

Que. – Which thermometer do not use mercury?

Ans. – Digital thermometer.
Que. – What is the range of clinical thermometer?

Ans. – 37 °C to 42 °C.

Que. – What is laboratory thermometer?

Ans. – The temperature of some other things are measured by a special kind of thermometer. Which range is generally –10°C to 110°C is known as laboratory thermometer.

Que. –Why should we use antiseptic solution to wash out the thermometer?

Ans. – After using the thermometer it get infected or may be isolated with germs.  So we use antiseptic solution to wash out the thermometer.

Que. – What is conduction?

Ans. – The process by which heat is transferred from the hotter end to the colder end of an object is known as conduction.

Que. – Why does a metallic pot get heated when we kept it on a flame?

Ans. – Due to conduction.

Que. – How does the sun’s heat reaches to us?

Ans. – The heat of the sun reaches us by radiation.

Que. – What is convection?

Ans. – The process of transferring of heat in liquid like water is known as convection.

Que. – Define conductor of heat? Write with examples.

Ans. – The materials which allow to pass the heat from themselves easily are  known as conductor of heat. EX. – copper, Iron, almunium etc.

Que. – Define bad conductor of heat with examples.

Ans. – the materials which does not allow to pass the heat from themselves are known as bad conductor of heat. Ex – wood, plastics etc.

Que. – What is radiation?

Ans. – The process of transferring the heat which does not need any medium is known as radiation. Ex – reaching the heat of the sun to us.

Que. – What are the modes to transfer the heat?

Ans. – There are three modes

(i)  Conduction

(ii) Convection

(iii) Radiation

Que. – Why does it seem comfortable to put on deep coloured clothes in winter?

Ans. – The deep coloured surface usually absorbs more heat, so putting on deep coloured clothes in winter is comfortable.

Que. – Which colour absorbs more heat?

Ans. – Black.

Que. – Why should we put on the white dress in summer?

Ans. – Light colour or white dress reflects the most of the heat radiation and absorbs less heat so that it keeps us comfortable.

Que. – Why do woolen clothes keep us warm in winter?

Ans. - woolen clothes keep us warm in winter because the wool is bad conductor of heat. The airs trap among its fibers.

Que. – by which mode of transferring of heat will take place in copper?

Ans. – conduction.

 

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