Alpha Question Bank for Medical: Physics>Chapter 16 - Heat Transfer>Exercise-1>Q 82

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The spectral emissive power of a black body at a temperature of $6000 K$ is maximum at $λ_{m} = 5000 \overset{\circ}{A} .$ If the temperature is increased by $10 %,$ then the decrease in $λ_{m}$ will be,

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Important Questions on Heat Transfer

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Alpha Question Bank for Medical: Physics>Chapter 16 - Heat Transfer>Exercise-1>Q 83

The rate of emission of energy by a unit area of a body is

10

watt and that of sun is

10^{6}

watt. The emissive power of the body is

0.1 .

If the temperature of the sun is

6000 K,

then the temperature of the body will be-

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Alpha Question Bank for Medical: Physics>Chapter 16 - Heat Transfer>Exercise-1>Q 84

The ratio of masses of two copper spheres of identical surfaces is

8 : 1 .

If their temperatures are

2000 K

and

1000 K

, respectively, then the ratio of energies radiated per second by the two is,

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Alpha Question Bank for Medical: Physics>Chapter 16 - Heat Transfer>Exercise-1>Q 85

A solid body is heated upto very high temperatures. As we go on heating, its brightness increases and it appears white at the end. The sequene of the colour observed as the temperature of the body increases will be-

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Alpha Question Bank for Medical: Physics>Chapter 16 - Heat Transfer>Exercise-1>Q 86

The effective area of a black body is

0.1 m^{2}

and its temperature is

100 K .

The amount of radiations emitted by it per min is -

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Alpha Question Bank for Medical: Physics>Chapter 16 - Heat Transfer>Exercise-1>Q 87

What is the energy of emitted radiation from Sun when the temperature is doubled

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Alpha Question Bank for Medical: Physics>Chapter 16 - Heat Transfer>Exercise-1>Q 88

Newton's law of cooling is a special case of

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Alpha Question Bank for Medical: Physics>Chapter 16 - Heat Transfer>Exercise-1>Q 89

A hot liquid is kept in a big room. Its temperature is plotted as a function of time. Which of the following curves may represent the plot?

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Alpha Question Bank for Medical: Physics>Chapter 16 - Heat Transfer>Exercise-1>Q 90

A body takes

4

minutes to cool from

100 ° C

to

70 ° C .

To cool from

70 ° C

to

40 ° C

it will take-(room temperature is

15 ° C

)