Based on the chapter Heat, some of the important questions are prepared in this question paper. The questions are covers from the Higher Order Thinking Questions and Value Based Questions.

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Questions:

Fill up / 1 Marks

5 x 1 = 5

Wool is a ______ conductor of heat.

In coastal areas, cold air flows in the day from sea to land. It is called ______

The normal temperature of human body is ______ ⁰C.

A cold steel spoon is dipped in a cup of hot milk. It transfers heat to its other end by the process of ______

The hotness of a body is determined by its ______

Generic 3

5 x 3 = 15

Briefly explain, why do the kites and eagles fly without flapping their wings.

Explain the reason for the shiny reflectors of room heaters.

Explain in brief, why we wear dark coloured clothes in winter and light coloured clothes in summer.

Differentiate between two modes of transfer of heat, i.e. convection and conduction.

10.

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

Multiple Choice Question

5 x 1 = 5

11.

Boojho has three thermometers as shown in figure. He wants to measure the temperature of his body and that of boiling water. Which thermometer(s) should he choose?

(a)

Thermometers (i) and (iii) for measuring body temperature and (ii) for measuring the temperature of boiling water

(b)

Thermometer (i) for measuring temperature of both

(c)

Thermometer (ii) for measuring temperature of both

(d)

Thermometer (iii) for measuring temperature of both

12.

Heat always flows

(a)

from a colder object to a hotter object

(b)

from a hotter object to a colder object

(c)

in both the directions

(d)

None of the above

13.

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

14.

A wooden spoon is dipped in a cup of icecream, then 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

15.

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

Generic 2

5 x 2 = 10

16.

How does the heat travel in air?

17.

Explain how do we find out how hot an object really is.

18.

Briefly mention one application of kink in the clinical thermometer.

19.

Name the mode of transfer of heat in which medium is not required.

20.

The radiators in cars are painted black. Explain why.

Generic 5

2 x 5 = 10

21.

Last Sunday, Pooja on her week off entered in her kitchen to cook rice for her family in lunch time. The moment she put fry pan on the gas stove and lighted it through the matchstick, all of sudden her 5 years small daughter entered into the kitchen and tends to touch the hot fry pan. At the same time, Pooja saw her and pushed her away from the hot fry pan. In this way, she saved her child.
(a) Explain why do the fry pan are provided with the plastic handles?
(b) Mention the values represented by Pooja here towards her 5 years small daughter.

22.

Explain the differences between heat and temperature.

True or False

5 x 1 = 5

23.

Water and air are good conductors of heat.

(a)

True

(b)

False

24.

Marking on clinical thermometer is from 0⁰C to 100⁰C.

(a)

True

(b)

False

25.

Water at higher temperature feels more hot.

(a)

False

(b)

True

26.

Normal temperature of human body is 98.6°C.

(a)

True

(b)

False

27.

Our sense of touch about hotness or coldness is not always reliable

(a)

False

(b)

True

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Answers Key:

Fill up / 1 Marks

5 x 1 = 5

()
poor

()
sea breeze

()
37

()
convection

()
temperature

Generic 3

5 x 3 = 15

As it is a fact that the hot air during the day time surrounds the land gradually and rises up, due to which a convection air of heat develops. So, kites and eagles start moving along this rising current of heat without flapping the wings to fly high up in the sky.

Since, the shiny surface absorbs very little heat due to which the reflectors reflect all the heat which makes the room heaters more effective. So, due to this reason, room heaters have shiny reflectors.

We wear dark coloured clothes in winter to keep us warm as they absorb all the heat radiation coming from the sun whereas light coloured clothes reflect most of the heat radiation coming from the sun that falls on them and therefore we feel more comfortable wearing them in the summer.

Difference between convection and conduction

Conduction	Convection
The mode of transfer of heat from the hotter part of a material to its colder part or from a hot material to a cold material in contact with it without the movement of material as a whole. So, this phenomenon is known as conduction.	The mode of transfer of heat from the hotter part a fluid to its colder parts by the movement of liquid itself. So, this phenomenon is known as convection.
In all the solids, heat is transferred by the process of conduction.	In all the liquids and gases, heat is transferred by the process of convection.

10.

Wearing more number of clothes makes air gap which do not allow heat to pass out but in case of one thick cloth it is not as such, so we should wear more layers of clothing during winter to keep us warmer.

Multiple Choice Question

5 x 1 = 5

11.

(a)
Thermometers (i) and (iii) for measuring body temperature and (ii) for measuring the temperature of boiling water

12.

(b)
from a hotter object to a colder object

13.

As copper is a better conductor of heat than the stainless steel. So, stainless steel pans are usually provided with copper bottom.

14.

It does not become cold because it is an insulator.

15.

As heat can only flow from higher temperature to lower temperature. Thus, the heat will not flow from iron ball to water or vice-versa.

Generic 2

5 x 2 = 10

16.

Heat travels in air through convection.

17.

By using thermometer, we can measure the degree of hotness of a body.

18.

The clinical thermometer consists of kink which prevents the mercury level from falling on its own.

19.

Radiation is the mode of transfer of heat in which medium is not required.

20.

Since, the black bodies are better radiators, so due to this reason, radiators in cars are painted black.

Generic 5

2 x 5 = 10

21.

(a) As we know that plastic is a bad conductor of heat which does not allow the heat to pass through itself. So, heat from the fry pan does not flow to the handle due to which we can hold it easily. So that's why, the fry pans are provided with the plastic handles.
(b) The value showed by Pooja here is a great concern and careness towards her five years old small daughter.

22.

The differences between heat and temperature are given as below

Heat	Temperature
It is a form of energy which flows from one body to another when there is a difference in temperature between the objects.	It is the thermal condition of a body that indicates whether or not and in which direction, heat will flow from one body to the other.
It is equal to the sum of internal energies of the molecules of a body.	It is proportional to average kinetic energy of the molecules of the body.
As a heat between two bodies, total amount of heat of two bodies remains unchanged.	As a conclusion of exchange of heat between two bodies sum of their temperatures before and after exchange is not same.
SI unit of heat is joule (J).	SI unit of temperature is kelvin (K).