2014
NEET
MCQ
AIPMT 2014
A thermodynamic system undergoes cyclic process ABCDA as shown in figure. The work done by the system in the cycle is
A.
P0V0
B.
2P0V0
C.
${{{P_0}{V_0}} \over 2}$
D.
zero
2014
NEET
MCQ
AIPMT 2014
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
NEET
MCQ
NEET 2013 (Karnataka)
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
A.
10 J
B.
12 J
C.
36 J
D.
6 J
2013
NEET
MCQ
NEET 2013 (Karnataka)
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
NEET
MCQ
NEET 2013 (Karnataka)
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
NEET
MCQ
NEET 2013 (Karnataka)
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
NEET
MCQ
NEET 2013
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
NEET
MCQ
NEET 2013
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?
A $ \to $ B $ \to $ C $ \to $ A, as shown. what is the net work done by the gas?
A.
Zero
B.
$-$ 2000 J
C.
2000 J
D.
1000 J
2013
NEET
MCQ
NEET 2013
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
NEET
MCQ
NEET 2013
In the given (V $-$ T) diagram, what is the relation between pressure P1 and P2?
A.
P2 < P1
B.
Carnot be predicted
C.
P2 = P1
D.
P2 > P1
2012
NEET
MCQ
AIPMT 2012 Mains
An ideal gas goes from state A to state B via three different processes as indicated in the P-V diagram.
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
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
NEET
MCQ
AIPMT 2012 Prelims
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.
B.
C.
D.
2012
NEET
MCQ
AIPMT 2012 Prelims
A thermodynamic system is taken through the cycle ABCD as shown in figure. Heat rejected by the gas during the cycle is
A.
2PV
B.
4PV
C.
${1 \over 2}$ PV
D.
PV
2011
NEET
MCQ
AIPMT 2011 Mains
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
NEET
MCQ
AIPMT 2011 Prelims
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
NEET
MCQ
AIPMT 2011 Prelims
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
NEET
MCQ
AIPMT 2010 Mains
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
NEET
MCQ
AIPMT 2010 Mains
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
NEET
MCQ
AIPMT 2010 Prelims
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 $W, in an isothermal process
2009
NEET
MCQ
AIPMT 2009
The internal energy change in a system that has absorbed 2 kcal of heat and done 500 J of work is
A.
6400 J
B.
5400 J
C.
7900 J
D.
8900 J
2009
NEET
MCQ
AIPMT 2009
In thermodynamic processes which of the following statements is not true ?
A.
In an isochoric process pressure remains constant.
B.
In an isothermal process the temperature remains constant.
C.
In an adiabatic process PV$\gamma $ = constant.
D.
In an adiabatic process the system is insulated from the surroundings.
2008
NEET
MCQ
AIPMT 2008
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
NEET
MCQ
AIPMT 2008
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
NEET
MCQ
AIPMT 2007
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
NEET
MCQ
AIPMT 2006
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
NEET
MCQ
AIPMT 2006
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
NEET
MCQ
AIPMT 2005
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
NEET
MCQ
AIPMT 2005
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
NEET
MCQ
AIPMT 2004
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)
(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
NEET
MCQ
AIPMT 2004
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
NEET
MCQ
AIPMT 2003
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
NEET
MCQ
AIPMT 2002
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
NEET
MCQ
AIPMT 2001
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
NEET
MCQ
AIPMT 2000
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
NEET
MCQ
AIPMT 2000
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