Achieve Indian Airforce Agniveer Vayu Physics Practice Book>Chapter 11 - Thermal Properties of Matter>Exercise>Q 3

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Important Questions on Thermal Properties of Matter

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Achieve Indian Airforce Agniveer Vayu Physics Practice Book>Chapter 11 - Thermal Properties of Matter>Exercise>Q 1

A body cools from

80^{o} C

to

50^{o} C

in

5

minutes. Calculate the time it takes to cool from

60^{o} C

to

30^{o} C

. The temperature of surroundings is

20^{o} C

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Achieve Indian Airforce Agniveer Vayu Physics Practice Book>Chapter 11 - Thermal Properties of Matter>Exercise>Q 2

In a room where the temperature is

30^{o} C

, a body cools from

61^{o} C

to

59^{o} C

in

4

minutes. The time taken by the body to cool from

51^{o} C

to

49^{o} C

is

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Achieve Indian Airforce Agniveer Vayu Physics Practice Book>Chapter 11 - Thermal Properties of Matter>Exercise>Q 3

Hot water cools from

60 ℃

to

50 ℃

in the first

10 \min

and to

42 ℃

in the next

10 \min

. Then the temperature of the surrounding is

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Achieve Indian Airforce Agniveer Vayu Physics Practice Book>Chapter 11 - Thermal Properties of Matter>Exercise>Q 4

In a room where the temperature is

30 ℃

, a body cools form

61 ℃

to

59 ℃

in 4 min. The time (in minutes) taken by the body to cool from

51 ℃

to

49 ℃

will be

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Achieve Indian Airforce Agniveer Vayu Physics Practice Book>Chapter 11 - Thermal Properties of Matter>Exercise>Q 5

Newton's law of cooling holds good only, if the temperature difference between the body and the surroundings is

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Achieve Indian Airforce Agniveer Vayu Physics Practice Book>Chapter 11 - Thermal Properties of Matter>Exercise>Q 6

A black body of mass

34.38 g

and surface area

19.2 c m^{2}

is at an initial temperature of

400 K

. It is allowed to cool inside an evacuated enclosure kept at constant temperature

300 K

. The rate of cooling is

0.04 ℃ s^{- 1}

. The specific heat of the body in

J k g^{- 1} K^{- 1}

is

(Stefan's constant

σ = 5.73 \times 10^{- 8} W m^{- 2} K^{- 4}

)

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Achieve Indian Airforce Agniveer Vayu Physics Practice Book>Chapter 11 - Thermal Properties of Matter>Exercise>Q 7

If a liquid takes

30 s

in cooling from

95 ° C

to

90 ° C

and

70 s

in cooling from

55 ° C

to

50 ° C

, then the temperature of the room is: