NCERT Solutions for Class 7 Science Chapter 4 Heat
You will find NCERT Solutions for Class 7 Science Chapter 4 Heat here that can be used to enrich knowledge and make lessons for learners more exciting. It is very challenging to score good marks in tests that is why we have prepared NCERT Solutions. Your marks play an important role in shaping future thus these NCERT Solutions for Science will become your comprehensive guide in easy learning and evaluating yourself.
Chapter 4 Light NCERT Questions and Answers can be used to enrich knowledge and make lessons for learners more exciting. These are helpful in building a great foundation of concepts and make easy for the students to understand basics. You develop the ability to effectively respond to the high end questions that you’re confronted with.
NCERT Solutions for Class 7 Science Chapter 4 Heat
These NCERT Solutions are prepared as per the accordance of latest CBSE guidelines so you can score maximum marks. Through these NCERT Solutions for Class 7 Science Chapter 4, students should not waste time and adopt a strategy that helps them operate and learn at maximum efficiency. It will make you understand the topics in most simple manner and grasp it easily to perform better.
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Page No: 45
Exercises
1. State similarities and differences between the laboratory thermometer and the clinical thermometer.
Answer
Similarities:
(i) both made up of uniform glass tube.
(ii) both contain mercury.
(iii) both have bulb at one end.
(iv) both generally have celcius scale.
Differences:
(i) Range of laboratory thermometer is from -10°C to 110°C while range of clinical thermometer is from 35°C to 42°C.
(ii) Laboratory thermometer is used to take the reading of temperature in laboratory while clinical thermometer is used to measure the temperature f human body.
(iii) Mercury level falls when removed from the source in case of laboratory thermometer while in case of clinical thermometer
2. Give two examples each of conductors and insulators of heat.
Answer
Examples of conductors : Iron, Copper
Examples of insulators : Plastic, 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. It transfers heat to its other end by the process of ______________.
(f ) Clothes of ______________ colours absorb 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. It transfers heat to its other end by the process of conduction.
(f) Clothes of dark colours absorb heat better than clothes of light colours.
Page No: 46
4. Match the following :
| Column I | Column II |
| (i) Land breeze blows during | (a) summer |
| (ii) Sea breeze blows during | (b) winter |
| (iii) Dark coloured clothes are preferred during | (c) day |
| (iv) Light coloured clothes are preferred during | (d) night |
Answer
| Column I | Column II |
| (i) Land breeze blows during | (d) night |
| (ii) Sea breeze blows during | (c) day |
| (iii) Dark coloured clothes are preferred during | (b) winter |
| (iv) Light coloured clothes are preferred during | (a) summer |
5. Discuss why wearing more layers of clothing during winter keeps us warmer than wearing just one thick piece of clothing.
Answer
We wear more layers of clothing during winter to keeps us warmer than wearing just one thick piece of clothing because because air gets trapped in between the two layers of blankets. This air prevents the flow of heat from our body to the cold surroundings as air is bad conductor of heat.
6. Look at Fig. 4.13. Mark where the heat is being transferred by conduction, by convection and by radiation.
Answer
Conduction: From pan to water.
Convection: Heat within water.
Radiation: From burner to pan.
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 colour is absorb least heat. It reflects most of the heat and hence keeps the house cooler.
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
► (d) between 30°C and 50°C
Heat gained by cold water will be equal to the lost by hot wate.
Page No: 47
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
► (b) not flow from iron ball to water or from water to iron ball.
Both have the same temperature.
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
► (d) does not become cold.
Wood is a bad conductor of heat.
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
► (c) copper is a better conductor of heat than the stainless steel.
Go Back To NCERT Solutions for Class 7 Science
Chapter 4 Heat Class 7 Science NCERT Solutions
Given NCERT Solutions are available in understandable language in order to be effective and perform better in the class. Detailed explanation provided under each NCERT solutions will help in understanding the concepts better. It will allow students to cover the entire syllabus effectively without any frustration.
Class 7 Science Chapter 4 Heat NCERT Questions and Answers - Topics
• Hot and Cold
• Measuring Temperature
→ Reading a thermometer
• Laboratory Thermometer
• Transfer of Heat
• Kinds Of Clothes We Wear In Summer and Winter
• Woollen clothes keep us warm in winter
Class 7 Science Chapter 4 Heat NCERT Questions and Answers - Notes
• A reliable measure of the hotness of an object is its temperature. Temperature is measured by a device called thermometer.
• The thermometer that measures our body temperature is called a clinical thermometer.
→ A clinical thermometer consists of a long, narrow, uniform glass tube. It has a bulb at one end. This bulb contains mercury. Outside the bulb, a small shining thread of mercury can be seen.
→ A clinical thermometer reads temperature from 35°C to 42°C.
• The normal temperature of human body is 37°C.
• Laboratory thermometer is used to measure the temperature. The scale of temperature is graduated generally from –10°C to 110°C over the glass tube. Each division of temperature scale is further divided into 10 parts to read fraction of temperature.
• The process by which heat is transferred from the hotter end to the colder end of an object is known as conduction. In solids, generally, the heat is transferred by the process of conduction.
• The materials which allow heat to pass through them easily are conductors of heat. For examples, aluminum, iron and copper.
• Poor conductors are known as insulators. The water and air are poor conductors of heat.
• The transfer of heat because of movement of the molecules of the medium; via mass transfer; is called convection or convection of heat.
→ Water and air are bad conductors of heat. But they do become hot, in spite of being bad conductors. Heat transfer in fluids takes place through convection.
• In the coastal areas, during the day, the land gets heated faster than the water. The air over the land becomes hotter and rises up. The cooler air from the sea rushes in towards the land to take its place. The warm air from the land moves towards the sea to complete the cycle. The air from the sea is called the sea breeze.
→ To receive the cooler sea breeze, the windows of the houses in coastal areas are made to face the sea. At night it is exactly the reverse. The water cools down more slowly than the land. So, the cool air from the land moves towards the sea. This is called the land breeze.
• From the sun the heat comes to us by another process known as radiation. The transfer of heat by radiation does not require any medium.
• In summer we prefer light-coloured clothes and in winter we usually wear dark-coloured clothes. Dark surfaces absorb more heat and, therefore, we feel comfortable with dark coloured clothes in the winter.
• In the winter, we use woollen clothes. Wool is a poor conductor of heat. Moreover, there is air trapped in between the wool fibres. This air prevents the flow of heat from our body to the cold surroundings. So, we feel warm.
Chapter 4 Heat Class 7 Science Questions and Answers - MCQ Questions with answers
1. Which of the following is the best conductor of heat?
(a) Water vapour
(b) Metals
(c) Alcohol
(d) Water
► (b) Metals
2. The clinical thermometers presently in use in India are marked with a temperature scale. This scale corresponds to which of the following?
(a) Celsius
(b) Fahrenheit
(c) Both (a) and (b)
(d) None of these
► (a) Celsius
3. Which of the following devices is used for measurement of temperature of human body?
(a) Stethoscope
(b) Clinical thermometer
(c) Laboratory thermometer
(d) None of the above
► (b) Clinical thermometer
4. A wooden spoon is dipped in cup of ice-cream, its other end
(a) Does not become cold
(b) Become cold by radiation
(c) Become cold by convection
(d) Become cold by conduction
► (a) Does not become cold
5. In which mode of heat transfer does the transfer of heat occur as a wave?
(a) Conduction
(b) Convection
(c) Radiation
(d) All of the above
► (c) Radiation
6. On a Fahrenheit scale
(a) Boiling point of water is 212∘F
(b) The temperature will be equal to that on the Celsius scale at −40∘C
(c) The difference between the upper fixed point and the lower fixed point is divided into 180 equal parts
(d) All of the above
► (d) All of the above
7. One feels sensation of heat when exposed to
(a) ultra violet rays
(b) infra-red rays
(c) X-rays
(d) gamma rays
► (b) infra-red rays
8. Which type of cloth is preferred in summer?
(a) Silk clothes
(b) Cotton clothes
(c) Nylon clothes
(d) Polyester clothes
► (b) Cotton clothes
9. The direction of flow of heat is
(a) always from hotter body to a cooler body
(b) always from cooler body to a hotter body.
(c) always from a body at a lower temperature to a body at higher temperature
(d) All of the above
► (a) always from hotter body to a cooler body
10. Land breeze blows from
(a) Upper surface to surface layer
(b) Lower surface to upper surface
(c) Land to Sea
(d) Sea to land
► (c) Land to Sea
NCERT Solutions for Class 7 Science Chapter 4 will improve your awareness skills sharply and you can easily memorize more things precisely. In the examinations, you will can come up with better answers and lay out the main point effectively. NCERT Solutions is an effective method for learning since you can be le to learn a lot within a short time.