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Heat and Thermodynamics

90 Questions Start NEET Test
All Exams NEET AIIMS
2015 Q51 NEET MCQ
10 Mar 2026
One mole of an ideal diatomic gas undergoes a transition from A to B along a path AB as shown in the figure.

AIPMT 2015 Cancelled Paper Physics - Heat and Thermodynamics Question 76 English

The change in internal energy of the gas during the transition is
A.
20 J
B.
$-$ 12 kJ
C.
20 kJ
D.
$-$ 20 kJ
2015 Q52 NEET MCQ
10 Mar 2026
A Carnot engine, having an efficiency of as heat engine, is used as a refrigerator. If the work done on the system is 10 J, the amount of energy absorbed from the reservoir at lower temperature is
A.
90 J
B.
1 J
C.
100 J
D.
99 J
2015 Q53 NEET MCQ
10 Mar 2026
The ratio of the specific heats ${{{C_p}} \over {{C_v}}} = \gamma $ in terms of degrees of freedom (n) is given by
A.
$\left( {1 + {2 \over n}} \right)$
B.
$\left( {1 + {n \over 2}} \right)$
C.
$\left( {1 + {1 \over n}} \right)$
D.
$\left( {1 + {n \over 3}} \right)$
2015 Q54 NEET MCQ
10 Mar 2026
Figure below shows two paths that may be taken by a gas to go from a state A to a state C.

AIPMT 2015 Cancelled Paper Physics - Heat and Thermodynamics Question 75 English
In process AB, 400 J of heat is added to the system and in process BC, 100 J of heat is added to the system. The heat absorbed by the system in the process AC will be
A.
460 J
B.
300 J
C.
380 J
D.
500 J
2014 Q55 NEET MCQ
10 Mar 2026
A monatomic gas at a pressure P, having a volume V expands isothermally to a volume 2V and then adiabatically to a volume 16V. The final pressure of the gas is (Take $\gamma $ = 5/3)
A.
64P
B.
32P
C.
P/64
D.
16P
2014 Q56 NEET MCQ
10 Mar 2026
A thermodynamic system undergoes cyclic process ABCDA as shown in figure. The work done by the system in the cycle is

AIPMT 2014 Physics - Heat and Thermodynamics Question 73 English
A.
P0V0
B.
2P0V0
C.
${{{P_0}{V_0}} \over 2}$
D.
zero
2014 Q57 NEET MCQ
10 Mar 2026
The mean free path of molecules of a gas, (radius r) is inversely proportional to
A.
r3
B.
r2
C.
r
D.
$\sqrt r $
2013 Q58 NEET MCQ
10 Mar 2026
A system is taken from state a to state c by two paths adc and abc as shown in the figure. The internal energy at a is ${U_a} = 10\,J$. Along the path adc the amount of heat absorbed dQ1 $=$ 50 J and the work obtained dW1 $=$ 20 J whereas along the path abc the heat absorbed dQ2 = 36 J. The amount of work allong the path abc is

NEET 2013 (Karnataka) Physics - Heat and Thermodynamics Question 67 English
A.
10 J
B.
12 J
C.
36 J
D.
6 J
2013 Q59 NEET MCQ
10 Mar 2026
In a vessel, the gas is at pressure P. If the mass of all the molecules is halved and their speed is doubled, then the resultant pressure will be
A.
2P
B.
P
C.
P/2
D.
4P
2013 Q60 NEET MCQ
10 Mar 2026
Two Carnot engines A and B are operated in series. The engine A receives heat from the source at temperature T1 and rejects the heat to the sink at temperature T. The second engine B receives the heat at temperature T and rejects to its sink at temperature T2. For what values of T the efficiencies of the two engines are equal
A.
${{{T_1} - {T_2}} \over 2}$
B.
${T_1}{T_2}$
C.
$\sqrt {{T_1}{T_2}} $
D.
${{{T_1} + {T_2}} \over 2}$
2013 Q61 NEET MCQ
10 Mar 2026
Which of the following relations does not give the equation of an adiabatic process, where terms have their usual meaning?
A.
P1$-$$\gamma $ T$\gamma $  =  constant
B.
PV$\gamma $   =  constant
C.
TV$\gamma $$-$1  =  constant
D.
P$\gamma $  T1$-$$\gamma $  =  constant
2013 Q62 NEET MCQ
10 Mar 2026
During an adiabatic process, the pressure of a gas is found to be proportional to the cube of its temperature. The ratio of ${{{C_p}} \over {{C_p}}}$ for the gas is
A.
${5 \over 3}$
B.
${3 \over 2}$
C.
${4 \over 3}$
D.
2
2013 Q63 NEET MCQ
10 Mar 2026
A gas is taken through the cycle
A $ \to $ B $ \to $ C $ \to $ A, as shown. what is the net work done by the gas?

NEET 2013 Physics - Heat and Thermodynamics Question 70 English
A.
Zero
B.
$-$ 2000 J
C.
2000 J
D.
1000 J
2013 Q64 NEET MCQ
10 Mar 2026
The amount of heat energy required to raise the temperature of 1 g of Helium at NTP, from T1K to T2K is
A.
${3 \over 4}{N_a}{k_B}\left( {{T_2} - {T_1}} \right)$
B.
${3 \over 4}{N_a}{k_B}\left( {{{{T_2}} \over {{T_1}}}} \right)$
C.
${3 \over 8}{N_a}{k_B}\left( {{T_2} - {T_1}} \right)$
D.
${3 \over 2}{N_a}{k_B}\left( {{T_2} - {T_1}} \right)$
2013 Q65 NEET MCQ
10 Mar 2026
In the given (V $-$ T) diagram, what is the relation between pressure P1 and P2?

NEET 2013 Physics - Heat and Thermodynamics Question 71 English
A.
P2 < P1
B.
Carnot be predicted
C.
P2 = P1
D.
P2 > P1
2012 Q66 NEET MCQ
10 Mar 2026
An ideal gas goes from state A to state B via three different processes as indicated in the P-V diagram.

AIPMT 2012 Mains Physics - Heat and Thermodynamics Question 62 English

If Q1, Q2, Q3 indicate the heat absorbed by the gas along the three processes and $\Delta $U1, $\Delta $U2, $\Delta $U3 indicate the change in internal energy along the three processes respectively, then
A.
Q1 > Q2 > Q3 and $\Delta $U1 = $\Delta $U2 = $\Delta $U3
B.
Q3 > Q2 > Q1 and $\Delta $U1 = $\Delta $U2 = $\Delta $U3
C.
Q1 = Q2 = Q3 and $\Delta $U1 > $\Delta $U2 > $\Delta $U3
D.
Q3 = Q2 = Q1 and $\Delta $U1 > $\Delta $U2 > $\Delta $U3
2012 Q67 NEET MCQ
10 Mar 2026
One mole of an ideal gas goes from an initial state A to final state B via two processes : It first undergoes isothermal expansion from volume V to 3V and then its volume is reduced from 3V to V at constant pressure. The correct P-V diagram representing the two process is
A.
AIPMT 2012 Prelims Physics - Heat and Thermodynamics Question 63 English Option 1
B.
AIPMT 2012 Prelims Physics - Heat and Thermodynamics Question 63 English Option 2
C.
AIPMT 2012 Prelims Physics - Heat and Thermodynamics Question 63 English Option 3
D.
AIPMT 2012 Prelims Physics - Heat and Thermodynamics Question 63 English Option 4
2012 Q68 NEET MCQ
10 Mar 2026
A thermodynamic system is taken through the cycle ABCD as shown in figure. Heat rejected by the gas during the cycle is

AIPMT 2012 Prelims Physics - Heat and Thermodynamics Question 39 English
A.
2PV
B.
4PV
C.
${1 \over 2}$ PV
D.
PV
2011 Q69 NEET MCQ
10 Mar 2026
A mass of diatomic gas $(\gamma = 1.4)$ at a pressure of 2 atmospheres is compressed adiabatically so that its temperature rises from 27oC to 927oC. The pressure of the gas in the final state is
A.
8 atm
B.
28 atm
C.
68.7 atm
D.
256 atm
2011 Q70 NEET MCQ
10 Mar 2026
When 1 kg of ice at 0oC melts to water at 0oC, the resulting change in its entropy, taking latent heat of ice to be 80 cal/oC, is
A.
273 cal/K
B.
8 $ \times $ 104 cal/K
C.
80 cal/K
D.
293 cal/K
2011 Q71 NEET MCQ
10 Mar 2026
During an isothermal expansion, a confined ideal gas does $-$ 150 J of work against its surroundings. This implies that
A.
150 J of heat has been removed from the gas
B.
300 J of heat has been added to the gas
C.
no heat is transferred because the process is isothermal
D.
150 J of heat has been added to the gas
2010 Q72 NEET MCQ
10 Mar 2026
A monatomic gas at pressure P1 and volume V1 is compressed adiabatically to ${{1 \over 8}^{th}}$ of its original volume. What is the final pressure of the gas?
A.
64P1
B.
P1
C.
16P1
D.
32P1
2010 Q73 NEET MCQ
10 Mar 2026
If cp and cv denote the specific heats (per unit mass of an ideal gas of molecular weight M, then
A.
cp $-$ cv = R/M2
B.
cp $-$ cv = R
C.
cp $-$ cv = R/M
D.
cp $-$ cv = MR
2010 Q74 NEET MCQ
10 Mar 2026
If $\Delta $U and $\Delta $W represent the increase in internal energy and work done by the system respectively in a thermodynamical process, which of the following is true ?
A.
$\Delta $U = $-$$\Delta $W, in an adiabtic process
B.
$\Delta $U = $\Delta $W, in an isothermal process
C.
$\Delta $U = $\Delta $W, in an adiabatic process
D.
$\Delta $U = $-$ $\Delta $W, in an isothermal process
2009 Q75 NEET MCQ
10 Mar 2026
The internal energy change in a system that has absorbed 2 kcal of heat and done 500 J of work is
A.
6400 J
B.
5400 J
C.
7900 J
D.
8900 J
2009 Q76 NEET MCQ
10 Mar 2026
In thermodynamic processes which of the following statements is not true ?
A.
In an isochoric process pressure remains constant.
B.
In an isothermal process the temperature remains constant.
C.
In an adiabatic process PV$\gamma $ = constant.
D.
In an adiabatic process the system is insulated from the surroundings.
2008 Q77 NEET MCQ
10 Mar 2026
At 10oC the value of the density of a fixed mass of an ideal gas divided by it pressure is x. At 110oC this ratio is
A.
${{10} \over {110}}x$
B.
${{283} \over {383}}x$
C.
$x$
D.
${{383} \over {283}}x$
2008 Q78 NEET MCQ
10 Mar 2026
If Q, E and W denote respectively the heat added, change in internal energy and the work done in a closed cyclic process, then
A.
E = 0
B.
Q = 0
C.
W = 0
D.
Q = W = 0
2007 Q79 NEET MCQ
10 Mar 2026
An engine has an efficiency of 1/6. When the temperature of sink is reduced by 62oC, its efficiency is doubled. Temperatures of the source is
A.
37oC
B.
62oC
C.
99oC
D.
124oC.
2006 Q80 NEET MCQ
10 Mar 2026
A Carnot engine whose sink is at 300 K has an efficiency of 40%. By how much should the temperature of source be increased so as to increase its efficiency by 50% of original efficiency ?
A.
380 K
B.
275 K
C.
325 K
D.
250 K
2006 Q81 NEET MCQ
10 Mar 2026
The molar specific heat at constant pressure of an ideal gas is (7/2) R. The ratio of specific heat at constant pressure to that at constant volume is
A.
9/7
B.
7/5
C.
8/7
D.
5/7
2005 Q82 NEET MCQ
10 Mar 2026
Which of the following processes is reversible?
A.
Transfer of heat by conduction
B.
Transfer of heat by radiation
C.
Isothermal compression
D.
Electrical heating of a nichrome wire.
2005 Q83 NEET MCQ
10 Mar 2026
An ideal gas heat engine operates in Carnot cycle between 227oC and 127oC. It absorbs 6 $ \times $ 104 cal of heat at higher temperature. Amount of heat converted to work is
A.
4.8 $ \times $ 104 cal
B.
6 $ \times $ 104 cal
C.
2.4 $ \times $ 104 cal
D.
1.2 $ \times $ 104 cal.
2004 Q84 NEET MCQ
10 Mar 2026
The equation of state for 5 g of oxygen at a pressure P and temperature T, when occupying a volume V, will be
(where R is the gas constant)
A.
PV = (5/32)RT
B.
PV = 5RT
C.
PV = (5/2)RT
D.
PV = (5/16) RT
2004 Q85 NEET MCQ
10 Mar 2026
One mole of an ideal gas at an initial temperature of T K does 6R joule of work adiabatically. If the ratio of specific heats of this gas at constant pressure and at constant volume is 5/3, the final temperature of gas will be
A.
(T + 2.4) K
B.
(T $-$ 2.4) K
C.
(T + 4) K
D.
(T $-$ 4) K
2003 Q86 NEET MCQ
10 Mar 2026
An ideal gas heat engine operates in a Carnot cycle between 227oC and 127oC. It absorbs 6 kcal at the height temperature. The amount of heat (in kcal) converted into work is equal to
A.
4.8
B.
3.5
C.
1.6
D.
1.2
2002 Q87 NEET MCQ
10 Mar 2026
The efficiency of Carnot engine is 50% and temperature of sink is 500 K. If temperature of source is kept constant and its efficiency raised to 60%, then the required temperature of sink will be
A.
100 K
B.
600 K
C.
400 K
D.
500 K
2001 Q88 NEET MCQ
10 Mar 2026
A scientist says that the efficiency of his heat engine which work at source temperature 127oC and sink temperature 27oC is 26%, then
A.
it is impossible
B.
it is possible but less probable
C.
it is quite probable
D.
data are incomplete.
2000 Q89 NEET MCQ
10 Mar 2026
To find out degree of freedom, the expansion is
A.
$f = {2 \over {\gamma - 1}}$
B.
$f = {{\gamma + 1} \over 2}$
C.
$f = {2 \over {\gamma + 1}}$
D.
$f = {1 \over {\gamma + 1}}$
2000 Q90 NEET MCQ
10 Mar 2026
The (W/Q) of a Carnot engine is 1/6, now the temperature of sink is reduced by 62oC, then this ratio becomes twice, therefore the initial temperature of the sink and source are respectively
A.
33oC, 67oC
B.
37oC, 99oC
C.
67oC, 33oC
D.
97 K, 37 K