CBSE
Multiple Choice QuestionsAn 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
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
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
The heat produced in a long wire is characterized by resistance, current and time through which the current passes. If the errors in measuring these quantities are respectively 1 %, 2% and 1%, then the total error in calculating the energy produced is
4%
6%
4/3 %
8%
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
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
N moles of a monoatomic gas is carried round the reversible rectangular cycle ABCDA as shown in the diagram. The temperature at A is To. The thermodynamic efficiency of the cycle is
15 %
50 %
20 %
25 %
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
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
