Thermodynamics CBSE Questions & Answers

Thermodynamics

This is Physics Class 11 Thermodynamics CBSE Questions & Answers. There are 15 questions in this test with each question having around four answer choices.

Questions & Answers

1
In which type of process is the volume constant
  • A
    Adiabatic process
  • B
    Isothermal process
  • C
    Isobaric process
  • D
    Isochoric process
    Correct
2
The heat engine takes
  • A
    heat \({{\rm{Q}}_{\rm{1}}}\) from a hot reservoir at temperature \({{\rm{T}}_{\rm{1}}}\) , releases heat \({{\rm{Q}}_{\rm{2}}}\) to a cold reservoir at temperature \({{\rm{T}}_{\rm{2}}}\) and delivers work W to the surroundings
    Correct
  • B
    heat \({{\rm{Q}}_{\rm{1}}}\) from a hot reservoir at temperature \({{\rm{T}}_{\rm{1}}}\), releases heat \({{\rm{Q}}_{\rm{2}}}\) to a hot reservoir at temperature \({{\rm{T}}_{\rm{2}}}\) and delivers work W to the surroundings
  • C
    heat \({{\rm{Q}}_{\rm{1}}}\) from a cold reservoir at temperature \({{\rm{T}}_{\rm{1}}}\), releases heat \({{\rm{Q}}_{\rm{2}}}\) to a cold reservoir at temperature \({{\rm{T}}_{\rm{2}}}\) and delivers work W to the surroundings
  • D
    heat \({{\rm{Q}}_{\rm{1}}}\) from a cold reservoir at temperature \({{\rm{T}}_{\rm{1}}}\), releases heat \({{\rm{Q}}_{\rm{2}}}\) to a hot reservoir at temperature \({{\rm{T}}_{\rm{2}}}\) and delivers work W to the surroundings
3
The efficiency (η) of a heat engine is defined by (W is the output and \({{\rm{Q}}_{\rm{1}}}\) the heat input)
  • A
    \(\eta \) = \({{{Q_1}} \over W}\)
  • B
    \(\eta \) = \({{2W} \over {{Q_1}}}\)
  • C
    \(\eta \) = \({W \over {{Q_1}}}\)
    Correct
  • D
    \(\eta \) = \({W \over {2{Q_1}}}\)
4
A refrigerator's working substance
  • A
    extracts heat \({{\rm{Q}}_{\rm{2}}}\) from the cold reservoir at temperature \({{\rm{T}}_{\rm{2}}}\), some external work W is done on it and heat \({{\rm{Q}}_{\rm{1}}}\) is released to the hot reservoir at temperature \({{\rm{T}}_{\rm{2}}}\)
  • B
    extracts heat \({{\rm{Q}}_{\rm{2}}}\) from the hot reservoir at temperature \({{\rm{T}}_{\rm{2}}}\), some external work W is done on it and heat \({{\rm{Q}}_{\rm{1}}}\) is released to the hot reservoir at temperature \({{\rm{T}}_{\rm{1}}}\)
  • C
    extracts heat \({{\rm{Q}}_{\rm{2}}}\) from the hot reservoir at temperature \({{\rm{T}}_{\rm{2}}}\), some external work W is done by it and heat \({{\rm{Q}}_{\rm{1}}}\) is released to the cold reservoir at temperature \({{\rm{T}}_{\rm{1}}}\)
  • D
    extracts heat \({{\rm{Q}}_{\rm{2}}}\) from the cold reservoir at temperature \({{\rm{T}}_{\rm{2}}}\), some external work W is done on it and heat \({{\rm{Q}}_{\rm{1}}}\) is released to the hot reservoir at temperature \({{\rm{T}}_{\rm{1}}}\)
    Correct
5
The coefficient of performance (\(\alpha \)) of a refrigerator is given by
  • A
    \(\alpha \) = \(W + {Q_2}\)
  • B
    \(\alpha \) = \({W \over {{Q_2}}}\)
  • C
    \(\alpha \) = \(W*{Q_2}\)
  • D
    \(\alpha \) = \({{{Q_2}} \over W}\)
    Correct
6
Kelvin-Planck statement of Second Law of Thermodynamics states that
  • A
    No process is possible whose sole result is the absorption of heat from a reservoir and the complete conversion of the heat into work.
    Correct
  • B
    Processes are not possible whose sole result is the absorption of heat from a reservoir and the partial conversion of the heat into work.
  • C
    No process is possible whose sole result is the absorption of heat from a reservoir and the partial conversion of the heat into work.
  • D
    Processes are possible whose sole result is the absorption of heat from a reservoir and the complete conversion of the heat into work.
7
Clausius statement of Second Law of Thermodynamics states that
  • A
    No process is possible whose sole result is the transfer of work from a hotter object to a hotter object
  • B
    No process is possible whose sole result is the transfer of heat from a hotter object to a colder object
  • C
    Many processes are possible whose sole result is the transfer of heat from a colder object to a hotter object
  • D
    No process is possible whose sole result is the transfer of heat from a colder object to a hotter object
    Correct
8
The spontaneous processes of nature are
  • A
    dynamic
  • B
    reversible
  • C
    static
  • D
    irreversible
    Correct
9
A thermodynamic process (state i \( \to \) state f) is reversible
  • A
    if the process can be turned back such that both the system and the surroundings return to their different states, with no other change anywhere else in the universe.
  • B
    if the process can be turned back such that both the system and the surroundings return to their original states, with no other change anywhere else in the universe.
    Correct
  • C
    if the process can be turned back such that both the system and the surroundings return to their original states, with lots of change in the universe.
  • D
    if the process can be turned back such that both the system and the surroundings return to different states, with lots of change in the universe.
10
The Carnot cycle consists of
  • A
    Two isobaric processes connected by two adiabatic processes
  • B
    Two isochoric processes connected by two adiabatic processes
  • C
    Two isothermal processes connected by two adiabatic processes
    Correct
  • D
    Two isothermal processes connected by two isobaric processes
11
No engine operating between two temperatures
  • A
    can have efficiency less than that of the Carnot engine
  • B
    can have efficiency equal to that of the Carnot engine
  • C
    can have efficiency greater than that of the Carnot engine
    Correct
  • D
    can have coefficient of performance greater than that of the Carnot engine
12
A geyser heats water flowing at the rate of 3.0 liters per minute from 27 \(^\circ \)C to 77 \(^\circ \)C. If the geyser operates on a gas burner, what is the rate of consumption of the fuel if its heat of combustion is 4.0 \( \times \) \({\rm{1}}{0^{\rm{4}}}\) J/g?
  • A
    14 g per min
  • B
    12 g per min
  • C
    16 g per min
    Correct
  • D
    18 g per min
13
What amount of heat must be supplied to 2.0 \( \times \) \({\rm{1}}{0^{-{\rm{2}}}}\) kg of nitrogen (at room temperature) to raise its temperature by 45 \(^\circ \)C at constant pressure? (Molecular mass of \({{\rm{N}}_{\rm{2}}}\)= 28; R = 8.3 J \({\rm{mo}}{{\rm{l}}^{-{\rm{1}}}}\) \({{\rm{K}}^{-{\rm{1}}}}\).)
  • A
    974
  • B
    954
  • C
    904
  • D
    934 J
    Correct
14
A cylinder with a movable piston contains 3 moles of hydrogen at standard temperature and pressure. The walls of the cylinder are made of a heat insulator, and the piston is insulated by having a pile of sand on it. By what factor does the pressure of the gas increase if the gas is compressed to half its original volume?
  • A
    2.44
  • B
    2.84
  • C
    3.04
  • D
    2.64
    Correct
15
In changing the state of a gas adiabatically from an equilibrium state A to another equilibrium state B, an amount of work equal to 22.3 J is done on the system. If the gas is taken from state A to B via a process in which the net heat absorbed by the system is 9.35 cal, how much is the net work done by the system in the latter case?
  • A
    17.2 J
  • B
    17.6 J
  • C
    17.9 J
  • D
    16.9 J
    Correct