Important Questions Class 7 Science Chapter 4 – Heat
Chapter 4 of Class 7 Science is about Heat. In our daily life, we come across many substances measuring different temperatures. Some are hot, while others are cold.
In this chapter, you will learn to find out how hot or cold an object is. The chapter introduces some important concepts about temperature and its measurement using a thermometer. A person’s body temperature is measured using a clinical thermometer, and a laboratory thermometer is used to measure the temperature of an object. You will also learn about the three ways of heat transmission: conduction, convection, and radiation.
Preparing for examinations is not as difficult as it sounds if you know how to do it. One important step in this is choosing appropriate and effective study materials.
Our expert panel of Extramarks has developed the most reliable study and practice materials such as NCERT solutions, CBSE revision notes, CBSE sample papers, and more to help students grasp all the concepts of the chapter easily. Extramarks is one of the most trusted online learning platforms for Class 1 to Class 12 students who want to create a strong foundation for future studies across all streams.
The Extramarks team understands the importance of students revising the chapter by solving questions. Hence, our team of Science teachers have prepared a comprehensive list of Class 7 Science Chapter 4 Important Questions taken from the NCERT textbook, NCERT exemplars, CBSE past years’ question papers, and other reference books, etc., for students to help revise the topics thoroughly and score well in the examination.
Important Questions Class 7 Science Chapter 4 – With Solutions
Practising questions is a form of active learning and a highly effective study method for students to revise the chapter and clear their doubts. Our team of experienced subject matter experts has carefully collated Science Class 7 Chapter 4 Important Questions from various sources. Step-by-step solutions to each question are provided to make the concepts clear. And these solutions are fully based on the latest NCERT exam guidelines, making them a very effective study material for students during their exam preparation.
Students are advised to register on the Extramarks website and access the complete list of solutions to these chapter-wise questions.
The below given list consists of a few questions and their answers from our Important Questions Class 7 Science Chapter 4:
Question 1. A copper ball at 50°C is dropped in a mug containing water at 50°C.
The heat will:
(a) Flow from the copper ball to water.
(b) Not flow from copper ball to water or from water to copper ball.
(c) Flow from water to copper ball.
(d) Increase the temperature of both.
Answer 1. (b) Not flow from copper ball to water or from water to copper ball.
Explanation: In the conduction process, heat flows from a body at a higher temperature to a body at a lower temperature. As the copper ball and water have the same temperature of 50°C, heat will not flow from the copper ball to the water or from the water to the copper ball.
Question 2. Fill in the blanks with the appropriate word below.
(a) Temperature of boiling water cannot be measured by a
_____________ thermometer.
(b) The hotness of an object is established by its __________.
(c) Temperature is measured in degrees ______________.
(d) No medium is required for the 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 2.
(a) Clinical
(b) Temperature
(c) Celsius ( °C )
(d) Radiation
(e) Conduction
(g) Dark
Question 3. A marble tile would feel cold as compared to a wooden tile on a
winter morning because the marble tile:
(a) Is polished while the wooden tile is not polished.
(b) It is a better conductor of heat than wooden tile.
(c) Is a poor conductor of heat than the wooden tile.
(d) Reflects more heat than wooden tile.
Answer 3. (b) Is a better conductor of heat than the wooden tile.
Explanation: Marble tile is a good conductor of heat as it allows heat to pass through it,
leaving the surface cool in the winter. On the other hand, wood is not a good conductor of heat as it does not allow heat to pass through it.
Question 4. Describe both similarities and differences between the laboratory thermometer and the clinical thermometer.
Answer 4. The table below shows the similarities and differences between laboratory and clinical thermometers.
| Similarities |
Differences |
- Both have a long, narrow, uniform glass tube
|
- A clinical thermometer measures temperature from 35°C to 45°C, while the range of a laboratory thermometer is -10°C to 110°C.
|
- Both have a bulb containing mercury at one end.
|
2) Clinical thermometer is used to measure human body temperature. A laboratory thermometer is used to measure an object’s temperature. |
- Both have a celsius scale as a unit of temperature.
|
3) A kink is present near the bulb of the clinical thermometer to prevent the movement of mercury. In contrast, the laboratory thermometer does not have a kink, as the movement of mercury is required to measure temperature change continuously. |
Question 5. At a camping pitch, there are tents of two shades – one made with white fabric and the other with black fabric. Which one would you choose for resting on a hot summer afternoon? Explain your choice. Would you prefer the same tent during winter?
Answer 5. During the hot summer afternoon, a white fabric tent will be better for resting, as the white colour reflects sunlight, keeping the tent cool. The black colour absorbs sunlight and is suitable during winter to keep warm compared to a white fabric tent house.
Question 6. A small quantity of curd is mixed with warm milk for setting curd. The curd’s microbes help set the mixture’s temperature between 35°C and 40°C. The setting of curd becomes difficult in places where the room temperature usually remains much below the range. Suggest a way to set curd in such a situation.
Answer 6. To set the curd at the required temperature between 35°C and 40°C.
- Alternatively, the container of the mixture can be wrapped in any poor conductor of heat material, such as wool.
- Keep the container near the gas stove while cooking.
Question 7. Match the following :
| (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 7. The matched table is below,
| (i) Land breeze blows during |
(a) Night |
| (ii) Sea breeze blows during |
(b) Day |
| (iii) Dark coloured clothes are preferred during |
(c) Winter |
| (iv) Light-coloured clothes are preferred during |
(d) Summer |
Question 8. Give two examples of conductors and insulators of heat.
Answer 8.
- Conductors—aluminium, copper
- Insulators—wool, plastic
Question 9. A beggar covered himself with a few layers of newspaper on a cold winter night. This kept him warm because:
(a) Friction between the layers of newspaper generates heat.
(b) Air trapped between multiple layers of newspaper is not a good conductor of heat.
(c) Newspaper is a good conductor of heat.
(d) Newspaper has a higher temperature than the
surrounding temperature.
Answer 9. (b) Air trapped between multiple layers of newspaper is not a good conductor of heat.
Explanation: A newspaper is not a conductor of heat. It is an insulator and does not allow heat or cold to pass through it. When the beggar wrapped himself with the layers of newspaper on a cold winter night, the cold air from the surroundings got trapped in the layers of the newspaper, which helped the beggar to keep his body temperature stable and warm.
Note: Heat always flows from a hot substance to a colder one until they reach the same temperature through three different processes- conduction, convection, and radiation. The materials that conduct heat to pass through are known as good conductors of heat, and the materials that resist and do not allow the heat to pass through are known as poor conductors of heat.
Question 10. A wooden spoon is dipped in a glass of hot water. Its other end:
(a) Becomes hot due to the process of conduction.
(b) Becomes hot due to the process of convection.
(c) Becomes hot due to the process of radiation.
(d) Does not become hot.
Answer 10. (d) Does not become hot.
Explanation: Heat transmission can happen in three ways:
Conduction: Conduction of heat is generally in solid materials. Materials such as copper, aluminium, etc., are a few examples of good conductors of heat as they allow heat to pass through them. On the contrary, materials like wood, glass, paper, etc., do not allow heat to pass through them, so they are poor heat conductors. A wooden spoon dipped in a glass of hot water will not absorb the heat as per the conduction concept. Hence, option (a) is not correct.
Convection: Heat transmission occurs between liquids and gases in the convection process. Hence, option (b) is not correct.
Radiation: This process does not require any medium to transfer heat. Heat waves are emitted by a hot object, which may be absorbed, reflected, or transmitted through cold bodies. The Sun transmits heat waves through a process called radiation. Hence, option (c) is not correct.
Question 11. A and B measured their body temperature. A found this to be 98.6 °F, and B recorded 37°C. Which of the following statements is true?
(a) A has a higher body temperature than B.
(b) B has a lower body temperature than A.
(c) Both have normal body temperature.
(d) Both are suffering from fever.
Answer 11. (c) Both have normal body temperature.
Explanation: As we know, the normal temperature of the human body is 37°C.
- The body temperature of B= 37°C.
So, B has a normal body temperature.
- The body temperature of A= 98.6 °F.
- Now Let’s find out the body temperature of A in °C with the help of the below equation.
The body temperature of A = 37°C. Hence, option (c) is the correct
Question 12. Explain why wearing more layers of clothing during winter keeps us
warm more than wearing just one thick piece of clothing.
Answer 12. In the winter, wearing more layers of clothing is better than just one thick piece of clothing because:
- Air and clothes are poor conductors of heat.
- The air gets trapped between the layers of these cloth fibres and prevents heat flow from our body to the cold surroundings. So, we feel warm.
Question 13. Stainless steel pans are commonly provided with copper bottoms. This could be because:
(a) Pans made from the Copper bottom are more durable.
(b) Such pans appear colourful.
(c) Copper conducts heat better than stainless steel.
(d) It’s also easier to clean than stainless steel.
Answer 13. (c) Copper conducts heat better than stainless steel.
Explanation: Copper has more conduction electrons compared to stainless steel. It directs the heat evenly throughout the pan and heats it faster.
Question 14. While measuring the temperature, a few sharp jerks are given to the clinical thermometer before using it. Why is it done so?
Answer 14. The jerk to the clinical thermometer aims to get an accurate temperature reading. The jerk will make the mercury flow into the bulb and lower the mercury level below its normal temperature.
Question 15. Why is it suggested not to hold the thermometer by its bulb while reading it?
Answer 15. It is suggested not to hold the thermometer by its bulb while reading it because the mercury may expand in the bulb and lead to an incorrect temperature reading due to our body temperature.
Benefits of Solving Important Questions Class 7 Science Chapter 4
With the help of up-to-date study materials and the latest examination content and format, students get familiar with the actual question and answer examination format. Students can benefit in many ways by referring to and practising the Chapter 4 Class 7 Science Important Questions available on the Extramarks website. MCQs, short and medium-format questions and answers, and long answer questions are provided with step-by-step solutions to make students well versed with various questions appearing in the CBSE examination.
A few of the benefits of referring to Important Questions Class 7 Science Chapter 4 are:
- The question bank has detailed solutions to all the questions in the textbook. Also, the tricky questions between chapters make students think laterally and apply the concepts learned in the chapter. Multiple choice questions have a significant weightage in final examinations and require a lot of critical thinking to solve the questions. Extramarks provides a complete list of chapter-wise multiple-choice questions to help students prepare effectively for examinations.
- The questions and answers to all the Important Questions in Class 7 Science Chapter 4 are prepared by our experienced science faculty members who follow the CBSE syllabus and NCERT guidelines.
- By rigorously practising these advanced level questions from the Important Questions Class 7 Science Chapter 4, students can thoroughly brush up on the concepts, analyse their shortcomings, and overcome them before facing their final examinations.
- The questions are collated by referring to various trusted sources, including NCERT textbooks, NCERT exemplar books, past years’ question papers, and other sources.
Students can register on the Extramarks website and get access to answers given in Important Questions Class 7 Science Chapter 4.
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