NCERT Solutions for Class 7 Science Chapter 4: Heat
In this page we have NCERT Solutions for Class 7 Science Chapter 3: Heat . Hope you like them and do not forget to like , social share
and comment at the end of the page.
Question 1
State similarities and differences between the laboratory thermometer and the clinical thermometer. Answer
Question 2
Give two examples each of conductors and insulators of heat. Answer
Examples of conductors: Iron, Copper
Examples of insulators: Plastic, Wood
Question 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 ______________ colors absorb heat better than clothes of light colors. Answer
(a) temperature.
(b) clinical thermometer.
(c) Celsius.
(d) radiation.
(e) conduction.
(f) dark. Question 4
Match the following:
Answer
Question 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 air gets trapped in between the two layers of blankets. And as air is bad conductor of heat, it prevents the flow of heat from our body to the cold surroundings Question 6
Look at the below figure, 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. Question 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. Question 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
Question 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. Question 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.
As Wood is a bad conductor of heat.
Question 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.
