What is the slope for an isothermal process?

• $\frac{\mathrm{P}}{\mathrm{V}}$

• $- \frac{\mathrm{P}}{\mathrm{V}}$

• Zero

• ∞

For an adiabatic process

• ΔS = 0

• Δu = 0

• Q = 0

• W = 0

For cyclic process which of the following quantity is zero? 

• ΔV

• Δu

• W

• ΔQ

Assertion:  During rapid pumping of air in tyres, air inside the tyre is hotter than atmospheric air.

Reason:  Adiabatic process occurs at very high rate.

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

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

• If assertion is true but reason is false.

• If both assertion and reason are false.

155.

The latent heat of vaporisation of a substance is always

• greater than its latent heat of fusion

• greater than its latent heat of sublimation

• equal to its latent heat of sublimation

• less than its latent heat of fusion

A reversible engine converts one-sixth of the heat input into work. When the temperature of the sink is reduced by   62°C, the efficiency of the engine is doubled. The temperatures of the source and sink are

• 99^oC, 37^oC

• 80^oC, 37^oC

• 95^oC, 37^oC

• 90^oC, 37^oC

Graph of specific heat at constant volume for a monoatomic gas is

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 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.

Assertion:  For  an  isothermal  process  in  an  ideal  gas,  the heat  obsorbed  by the  gas is  entirely  used   in  the  work  done  by  the  gas. 

Reason:  During  a  process  taking  place in  a  system, the temperature remains constant then the  process is isothermal.

• 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

A slab consists of two layers of different materials of the same thickness and having thermal conductivities  K₁ and K₂  are connected in series. The equivalent thermal conductivity of the slab is

• $\frac{2 {\mathrm{K}}_1 {\mathrm{K}}_2}{{\mathrm{K}}_1 + {\mathrm{K}}_2}$

• $\sqrt{{\mathrm{K}}_1 {\mathrm{K}}_2}$

• $\frac{{\mathrm{K}}_1 {\mathrm{K}}_2}{{\mathrm{K}}_1 + {\mathrm{K}}_2}$

• K₁ + K₂