Emissive and absorptive power of a material at from Class Physics Thermal Properties of Matter

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NEET Physics : Thermal Properties of Matter

Multiple Choice Questions

61.

1 g of steam is sent into 1 g of ice. At thermal equilibrium, the resultant temperature of mixture is

  • 270oC

  • 230oC

  • 100oC

  • 120oC



62.

Emissive and absorptive power of a material at 2000 K is 8 and 10 respectively, calculate the emissivity of IBB (Ideal black body)

  • 0.2

  • 0.4

  • 0.6

  • 0.8



63.

In  a  metal  with  positive  Thomson  coefficient, current is  passed  from  the  lower  temperature  to  higher   temperature  to  higher  temperature  side. The  heat  will   be

  • absorbed

  • constant

  • evolved

  • either 'b' or 'c'



64.

Two conductors having same width and length, thickness d1 and d2 thermal conductivity K1 and K2 are placed one above the another. Find the equivalent thermal conductivity.

  • d1+ d2 K1 d2 + K2 d12 K1 + K2

  • d1 - d2 K1 d2 + K2 d12 K1 + K2

  • K1 d1 + K2 d2d1 + d2

  • K1 + K2d1 + d2



65.

Assertion:   When hot  water  is  poured  in  a  beaker of  thick  glass,  the  beaker cracks. 

Reason:  Outer surface of the beaker expands suddenly.

  • If both assertion and reason are true and reason is the correct explanation of assertion

  • If both assertion and reason are true but reason is not the correct explanation of assertion

  • If assertion is true but reason is false

  • If both assertion and reason are false



66.

When a current is passed in a conductor, 3o C rise in temperature is observed. If the strength of current is made thrice, then rise in temperature will approximately be

  • 36oC

  • 27o C

  • 18o C

  • 9o C



67.

Assertion:  Maximum air flow due to convection does not occur at the north pole but it occurs at 30°N. 

Reason: There is maximum temperature difference between equator and 30° N.

  • If both assertion and reason are true and reason is the correct explanation of assertion.

  • If both assertion and reason are true but reason is not the correct explanation of assertion.

  • If assertion is true but reason is false.

  • If both assertion and reason are false.



68.

Dimensional formula of ΔQ, heat supplied to the system is given by

  • [ M1 L2 T-2 ]

  • [ M1 L1 T-2 ]

  • [ M1 L2 T-1 ]

  • [M1 L1 T-1 ]



69.

Assertion: CP is always greater than CV in gases.

Reason: Work done at constant pressure is more than at constant volume

  • If both assertion and reason are true and reason is the correct explanation of assertion.

  • If both assertion and reason are true but reason is not the correct explanation of assertion.

  • If assertion is true but reason is false.

  • If both assertion and reason are false.



70.

Assertion:  Water kept in an open vessel will quickly evaporate on the surface of the moon. 

Reason:  The temperature at the surface of the moon is much higher than the boiling point of water.

  • If both assertion and reason are true and reason is the correct explanation of assertion.

  • If both assertion and reason are true but reason is not the correct explanation of assertion.

  • If assertion is true but reason is false.

  • If both assertion and reason are false.



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