NCERT Solutions for Class 7 Science Chapter 4 Heat

 

NCERT solutions for class 7 science chapter 4 Heat - How do we know whether an object is hot or cold? Hot and cold are relative terms. That is one can say that ice is cold compared to water or water is hot compared to ice. The solutions of NCERT class 7 science chapter 4 heat discuss questions related to the concepts of heat and temperature. Temperature is the measure of hotness and thermometer is used to measure temperature. CBSE NCERT solutions for class 7 science chapter 4 heat have questions related to different types of thermometer. That is clinical and laboratory thermometer. Clinical thermometer is used to measure our body temperature. The normal temperature of the human body is 37°C and the range of the clinical thermometer is from 35°C to 42°C. For other temperature measurements, laboratory thermometers are used. The range of these thermometers is usually from –10°C to 110°C. How temperature is measured using a thermometer, how heat is transferred through convection, conduction and radiation and what is sea breeze and land breeze etc; NCERT class 7 chapter heat gives answers to all these questions. The NCERT solutions for class 7 science chapter 4 heat covers questions from all the topics covered in the chapter. At the end of each chapter, there are exercise questions for practice. Try to solve these questions and if any doubt arises refer to NCERT solutions for the respective chapter. 

Topics of NCERT class 7 science chapter 4 Heat:

4.1 Hot and Cold

4.2 Measuring Temperature

    Reading a Thermometer

4.3 Laboratory Thermometer

4.4 Transfer of Heat

4.5 Kinds of Clothes We Wear in Summer and Winter

    Woollen Clothes Keep Us Warm in Winter

NCERT solutions for class 7 science chapter 4 heat exercise:

1. State similarities and differences between the laboratory thermometer and the clinical thermometer.

Answer:

Similarities:-
i) In both laboratory thermometer and clinical thermometer, mercury is used

ii) Both laboratory and clinical thermometer consist of a long, narrow uniform tube of glass.

Differences:-

i) The least count of both the thermometer is different.

ii) Range of the temperature in a laboratory thermometer is from -10\degree C \ to \ 110\degree C  whereas in  clinical thermometer, it is from 35\degree C \ to \ 42\degree C

iii) Clinical thermometer is used to measure body temperature whereas laboratory thermometer is not used for such purposes 

2. Give two examples each of conductors and insulators of heat.

Answer:

Two examples of

i) Conductor :- 
1) Copper
2) Aluminium

ii) insulator:-
1) Plastic 
2)  Wood

3. Fill in the blanks :

(a) The hotness of an object is determined by its __________.

(b) Temperature of boiling water cannot be measured by a _____________ thermometer.

(c) Temperature is measured in degree ______________.

(d) No medium is required for transfer of heat by the process of __________.

(e) A cold steel spoon is dipped in a cup of hot milk. Heat is transferred to its other end by the process of ______________.

(f ) Clothes of ______________ colours absorb more heat better than clothes of light colours.

Answer:

a)   The hotness of an object is determined by its  temperature.

b)  Temperature of boiling water cannot be measured by a clinical thermometer.

c)  Temperature is measured in degree  celsius.

d)  No medium is required for transfer of heat by the process of radiation.

e)   A cold steel spoon is dipped in a cup of hot milk. Heat is transferred to its other end by the process of conduction.

f)  Clothes of  dark colours absorb more heat better than clothes of light colours.

5. Why wearing more layers of clothing during winter keeps us warmer than wearing just one thick piece of clothing.

Answer:

During winters, wearing more layers of clothing keeps us warmer more than compared to wearing just one thick piece of clothing because air gets trapped in between the layers of various clothes and as being a bad conductor of heat, air prevents heat loss from our body.

Because of that, wearing more layers of clothing during winter keeps us warmer than wearing just one thick piece of clothing. 

6.  Look at Fig. 4.13. Mark where the heat is being transferred by conduction, by convection and by radiation.

 

Answer:

Three stages are:-

i)  Transfer of heat from the burner to the pan takes place through radiation.

ii) Transfer of heat from the pan to water is taking place through conduction.

iii) Transfer of heat within water is take place through convection.

7. In places of hot climate it is advised that the outer walls of houses be painted white. Explain.

Answer:

In places of hot climate, it is advised that the outer walls of houses be painted white because white is a light colour and because of that it reflects back most of the heat that falls on it and a very less amount of heat is absorbed by the walls.
Therefore, a light colour tends to keep the house cool.

8. One litre of water at 30°C is mixed with one litre of water at 50°C. The temperature of the mixture will be

(a) 80°C

(b) more than 50°C but less than 80°C

(c) 20°C

(d) between 30°C and 50°C

Answer:

If one litre of water at 30\degree C is mixed with one litre of water at 50\degree C. Then, the temperature of the mixture will be

(d) between 30\degree C and  50\degree C

Because as the volume of both the liquids with temperature  30\degree C and  50\degree C is equal. Therefore, when we add both the liquids there is transferred of heat take place from a liquid with high temperature to a liquid with a low temperature. That's why temperature is between 30\degree C and  50\degree C 

9. An iron ball at 40°C is dropped in a mug containing water at 40°C. The heat will

(a) flow from iron ball to water.

(b) not flow from iron ball to water or from water to iron ball.

(c) flow from water to iron ball.

(d) increase the temperature of both.

Answer:

If an iron ball at  40\degree C  is dropped in a mug containing water at 40\degree C.  Then, the heat will

(b) not flow from iron ball to water or from water to iron ball.

Because heat will flow from an object with high temperature to an object having a low temperature.  But here the temperature of both liquid and iron ball is the same.
Therefore, no flow of heat takes place  

10. A wooden spoon is dipped in a cup of ice cream. Its other end

(a) becomes cold by the process of conduction.

(b) becomes cold by the process of convection.

(c) becomes cold by the process of radiation.

(d) does not become cold.

Answer:

If a wooden spoon is dipped in a cup of ice cream. Then, its other end

(d) does not become cold.

Because wood is a bad conductor of heat.
Therefore, no or very very less transfer of heat takes place.

11. Stainless steel pans are usually provided with copper bottoms. The reason for this could be that

(a) copper bottom makes the pan more durable.

(b) such pans appear colourful.

(c) copper is a better conductor of heat than the stainless steel.

(d) copper is easier to clean than the stainless steel.

Answer:

Stainless steel pans are usually provided with copper bottoms. The reason for this could be that

(c) copper is a better conductor of heat than stainless steel.

Chapterwise NCERT solutions of class 7 science

Chapter No.

Chapter Name

Chapter 1  

NCERT solutions for class 7 science chapter 1 Nutrition in Plants

Chapter 2

Solutions of NCERT class 7 science chapter 2 Nutrition in Animals

Chapter 3

CBSE NCERT solutions for class 7 science chapter 3 Fibre to Fabric

Chapter 4

NCERT solutions for class 7 science chapter 4 Heat

Chapter 5

Solutions of NCERT class 7 science chapter 5 Acids Bases and Salts

Chapter 6

CBSE NCERT solutions for class 7 science chapter 6 Physical and Chemical Changes

Chapter 7

NCERT solutions for class 7 science chapter 7 Weather Climate and Adaptations of Animals to Climate

Chapter 8

Solutions of NCERT class 7 science chapter 8 Winds storms and cyclones

Chapter 9

CBSE NCERT solutions for class 7 science chapter 9 Soil

Chapter 10

NCERT solutions for class 7 science chapter 10 Respiration in Organisms

Chapter 11

Solutions of NCERT class 7 science chapter 11 Transportation in Animals and Plants

Chapter 12

CBSE NCERT solutions for class 7 science chapter 12 Reproduction in Plants

Chapter 13

NCERT solutions for class 7 science chapter 13 Motion and Time

Chapter 14

Solutions of NCERT class 7 science chapter 14 Electric Current and its Effects

Chapter 15

CBSE NCERT solutions for class 7 science chapter 15 Light

Chapter 16

NCERT solutions for class 7 science chapter 16 Water A Precious Resource

Chapter 17     Solutions of NCERT class 7 science chapter 17 Forests Our Lifeline

Chapter 18

CBSE NCERT solutions for class 7 science chapter 18 Wastewater Story

NCERT Solutions for Class 7 Subject Wise

NCERT Solutions for Class 7 Maths

CBSE NCERT Solutions for Class 7 Science

Importance of  NCERT solutions for class 7 science chapter 4 heat:

  • An exactly similar or similar type of questions from NCERT book may appear in the class exams. So it is important to go through these questions. In the chapter heat, there are 11 exercise questions and the NCERT solutions for class 7 science chapter 4 heat explains all these questions.
  • For school students, teachers may give homework every day. The NCERT solutions for class 7 science chapter 4 heat helps to solve homework problems related to the chapter.
 

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