### Physics - Thermal Properties of Matter

#### Question - 1

Heat given to a system can be associated with

• A kinetic energy of random motion of molecules
• B kinetic energy of orderly motion of molecules
• C total kinetic energy of random and orderly motion of molecules
• D kinetic energy of random motion in some cases and kinetic energy of orderly motion in other

#### Question - 2

At what temperature (in o C), the fahrenheit and celsius scale gives same reading?

• A 40
• B -40
• C 8
• D -8

#### Question - 3

A bimetallic strip is made of aluminium and steel $\left( { \alpha }_{ Al }>{ \alpha }_{ steel } \right)$ on heating, the strip will

• A remain straight
• B get twisted
• C get twisted
• D bend with aluminium on concave side

#### Question - 4

If a piece of metal is heated to temperature $\theta$ and then allowed to cool in a room which is at temperature $\theta _0$, the graph between the temperature T of the metal and time t will be closed to

• A
• B
• C
• D

#### Question - 5

The radius of metal sphere at room temperature T is R and the coefficient of linear expansion of the metal is $\alpha$ . The sphere is heated a little by a temperature T so that, new temperature is $T+\Delta T.$ The increase in volume of sphere is approximately

• A $2\pi R\alpha \Delta T$
• B $\pi { R }^{ 2 }\alpha \Delta T$
• C $4\pi { R }^{ 3 }\alpha \Delta T/3$
• D $4\pi { R }^{ 3 }\alpha \Delta T$

#### Question - 6

Which one of the following would raise the temperature of 40 g of water at 20o C most mixed with?

• A 20 g of water at 40o C
• B 30 g of water at 30o C
• C 10 g of water at 60o C
• D 4 g of water at 100o C

#### Question - 7

A black body is at 2000 K, it emits maximum energy at a wavelength 1$\mu m$The temperature, it emits at wavelength of 2$\mu m$  is

• A 1000 K
• B 2000 K
• C 500 K
• D 100 K

#### Question - 8

A star emits wavelength 289.8 nm of maximum intensity. Then, radiant intensity of state is $(\sigma =5.67\times { 10 }^{ -8 }W/{ m }^{ 2 }/{ k }^{ 4 },$ Wein's constant, b=2898X10-6 mK)

• A 5.67X1016 W/m2
• B 5.67X1014 W/m2
• C 5.67X1010 W/m2
• D 5.67X108 W/m2

#### Question - 9

Wein's displacement law for emission of radiation can be written as

• A ${ \lambda }_{ max }$  is inversely proportional to square of absolute temperature (T2)
• B ${ \lambda }_{ max }$ is inversely proportional to absolute temperature (T)
• C ${ \lambda }_{ max }$ is directly proportional to absolute temperature (T)
• D ${ \lambda }_{ max }$ is inversely proportional to square of absolute temperature (T2 )

#### Question - 10

If temperature of black body increases from 300 K to 900 K, then the rate of energy radiation increase by

• A 81
• B 3
• C 9
• D 2