Assertion:  When a glass of hot milk is placed in a room and allowed to cool, its entropy decreases. 

Reason:  Allowing hot object to cool does not violate the second law of thermodynamics.

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

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

• If assertion is true, but reason is false

• Both assertion and reason are false statement

Assertion: Reversible systems are difficult to find in real world. 

Reason : Most processes are dissipative in nature.

• 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: Air quickly leaking out of a balloon becomes cooler

Reason: The leaking air undergoes adiabatic expansion

• 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:  In pressure-temperature (P-T) phase diagram of water, the slope of the melting curve is found to be negative. 

Reason:  Ice contracts on melting to 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

N  moles of a monoatomic gas is carried round the reversible rectangular cycle ABCDA as shown in the diagram. The temperature at A  is T_o. The thermodynamic efficiency of the cycle is

• 15 %

• 50 %

• 20 %

• 25 %

Assertion: Thermodynamic process in nature are irreversible.

Reason: Dissipative effects cannot be eliminated.

• 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: When a bottle of cold carbonated drink is opened, a slight fog forms around the opening. 

Reason:  Adiabatic expansion of the gas causes lowering of temperature and condensation of water vapours.

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

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

• if assertion is true but reason is false

• if both assertion and reason are false statements

178.

The density of a substance  at  0^°C  is 10 g/cc and at  100^° C, its density is  9.7  g/cc. The coefficient of linear expansion of the substance is

• 10^-4

• 10²

• 10^-3

• 10²

The latent heat of vapourisation of water is  2240. If the work done in the process of vapourisation of 1 g is 168 J, then increase in internal energy is

• 2408 J

• 2072 J

• 2240 J

• 1904 J

An engine is working. It takes 100 calories of heat from source and leaves 80 calories of heat to sink. If the temperature of source is 127°C, then temperature of sink is

• 147°C

• 47°C

• 100^°C

• 47 K