Question 1: Palette 1/90

NEET 2026 MCQ

A flask contains argon and chlorine in the ratio of $2: 1$ by mass. The temperature of the mixture is $27^{\circ} \mathrm{C}$. The ratio of root mean square speed of the molecules of the two gases $\left(\frac{V_{\mathrm{rms}}^{\mathrm{Ar}}}{V_{\mathrm{rms}}^{\mathrm{Cl}}}\right)$ is:

(Atomic mass of argon $=40.0 \mathrm{u}$ and molecular mass of chlorine $=70.0 \mathrm{u}$ )

A

$\frac{\sqrt{7}}{2}$

B

$\frac{7}{4}$

C

$\frac{7}{2}$

D

$\frac{2}{\sqrt{7}}$

Question 2: Palette 2/90

NEET 2026 MCQ

An electric heater supplies heat to a system at a rate of 100 W . If the system performs work at a rate of $75 \mathrm{~J} / \mathrm{s}$, then the rate at which internal energy increases will be:

A

75 W

B

100 W

C

125 W

D

25 W

Question 3: Palette 3/90

NEET 2026 MCQ

The temperature of a metallic sphere of radius $R$ is increased by a small amount $\Delta T$. If the linear coefficient of thermal expansion of the metal is $\alpha$, the approximate increase in the volume of the sphere is:

A

$6 \pi R^3 \alpha \Delta T$

B

$2 \pi R^3 \alpha \Delta T$

C

$3 \pi R^3 \alpha \Delta T$

D

$4 \pi R^3 \alpha \Delta T$

Question 4: Palette 4/90

NEET 2026 MCQ

In an adiabatic expansion, the temperature of one mole of an ideal monatomic gas ( $\gamma=5 / 3$ ) decreases from 60 K to 50 K . The work done by the gas in the process is:

(Take the universal gas constant as $R=8.3 \mathrm{~J} \mathrm{~mol}^{-1} \mathrm{~K}^{-1}$ )

A

166 J

B

41.5 J

C

83 J

D

124.5 J

Question 5: Palette 5/90

NEET 2026 MCQ

An ideal gas is made of polyatomic molecules. Each of the molecules has three translational, three rotational and $f$ number of vibrational modes. If the ratio of heat capacities $C_P / C_V$ of the gas is $8 / 7$, then the value of $f$ is:

A

1

B

4

C

3

D

2

Question 6: Palette 6/90

NEET 2026 MCQ

The mean free path of molecules in an ideal gas $A$ is half that of another ideal gas $B$. The diameter of the spherical molecules of gas $A$ is twice the diameter of the molecules of $B$. If number densities of the gases $A$ and $B$ are $n_A$ and $n_B$, respectively, the correct option is:

A

$n_A=\frac{1}{2} n_B$

B

$n_A=n_B$

C

$n_A=2 n_B$

D

$n_A=\frac{1}{4} n_B$

Question 7: Palette 7/90

NEET 2026 MCQ

One mole of an ideal monatomic gas undergoes a cyclic process as shown in the figure. The total heat supplied to the gas is:

A

800 J

B

400 J

C

500 J

D

600 J

Question 8: Palette 8/90

NEET 2025 MCQ

Three identical heat conducting rods are connected in series as shown in the figure. The rods on the sides have thermal conductivity $2 K$ while that in the middle has thermal conductivity $K$. The left end of the combination is maintained at temperature $3 T$ and the right end at $T$. The rods are thermally insulated from outside. In steady state, temperature at the left junction is $T_1$ and that at the right junction is $T_2$. The ratio $T_1 / T_2$ is

A

$\frac{5}{3}$

B

$\frac{5}{4}$

C

$\frac{3}{2}$

D

$\frac{4}{3}$

Question 9: Palette 9/90

NEET 2025 MCQ

A container has two chambers of volumes $V_1=2$ litres and $V_2=3$ litres separated by a partition made of a thermal insulator. The chambers contain $n_1=5$ and $n_2=4$ moles of ideal gas at pressures $p_1=1 \mathrm{~atm}$ and $p_2=2 \mathrm{~atm}$, respectively. When the partition is removed, the mixture attains an equilibrium pressure of

A

1.4 atm

B

1.8 atm

C

1.3 atm

D

1.6 atm

Question 10: Palette 10/90

NEET 2025 MCQ

An oxygen cylinder of volume 30 litre has 18.20 moles of oxygen. After some oxygen is withdrawn from the cylinder, its gauge pressure drops to 11 atmospheric pressures at temperature $27^{\circ} \mathrm{C}$. The mass of the oxygen withdrawn from the cylinder is nearly equal to:

[Given, $R=\frac{100}{12} \mathrm{~J} \mathrm{~mol}^{-1} \mathrm{~K}^{-1}$, and molecular mass of $\mathrm{O}_2=32,1$ atm pressure $=1.01 \times 10^5 \mathrm{~N} / \mathrm{m}$]

A

0.116 kg

B

0.156 kg

C

0.125 kg

D

0.144 kg

Question 11: Palette 11/90

NEET 2025 MCQ

Two gases $A$ and $B$ are filled at the same pressure in separate cylinders with movable pistons of radius $r_A$ and $r_B$, respectively. On supplying an equal amount of heat to both the systems reversibly under constant pressure, the pistons of gas $A$ and $B$ are displaced by 16 cm and 9 cm , respectively. If the change in their internal energy is the same, then the ratio $\frac{r_A}{r_B}$ is equal to

A

$\frac{2}{\sqrt{3}}$

B

$\frac{\sqrt{3}}{2}$

C

$\frac{4}{3}$

D

$\frac{3}{4}$

Question 12: Palette 12/90

NEET 2024 MCQ

Given below are two statements: One is labelled as Assertion $\mathbf{A}$ and the other is labelled as Reason $\mathbf{R}$.

Assertion A: Houses made of concrete roofs overlaid with foam keep the room hotter during summer.

Reason R: The layer of foam insulation prohibits heat transfer, as it contains air pockets.

In the light of the above statements, choose the correct answer from the options given below.

A

A is true but R is false.

B

A is false but R is true.

C

Both A and R are true and R is the correct explanation of A.

D

Both A and R true but R is NOT the correct explanation of A.

Question 13: Palette 13/90

NEET 2024 MCQ

The equilibrium state of a thermodynamic system is described by

A. Pressure

B. Total heat

C. Temperature

D. Volume

E. Work done

Choose the most appropriate answer from the options given below.

A

A, B and E only

B

B, C and D only

C

A, B and C only

D

A, C and D only

Question 14: Palette 14/90

NEET 2024 MCQ

According to the law of equipartition of energy, the number of vibrational modes of a polyatomic gas of constant $\gamma=\frac{C_p}{C_v}$ is ($C_P$ where $C_V$ are the specific heat capacities of the gas at constant pressure and constant volume, respectively):

A

$\frac{4+3 \gamma}{\gamma-1}$

B

$\frac{3+4 \gamma}{\gamma-1}$

C

$\frac{4-3 \gamma}{\gamma-1}$

D

$\frac{3-4 \gamma}{\gamma-1}$

Question 15: Palette 15/90

NEET 2024 MCQ

A thermodynamic system is taken through the cycle $abcda$. The work done by the gas along the path $b c$ is:

A

Zero

B

30 J

C

$-$90 J

D

$-$60 J

Question 16: Palette 16/90

NEET 2024 MCQ

The following graph represents the $T$-$V$ curves of an ideal gas (where $T$ is the temperature and $V$ the volume) at three pressures $P_1, P_2$ and $P_3$ compared with those of Charles's law represented as dotted lines.

Then the correct relation is :

A

$P_3>P_2>P_1$

B

$P_1>P_3>P_2$

C

$P_2>P_1>P_3$

D

$P_1>P_2>P_3$

Question 17: Palette 17/90

NEET 2023 MCQ

For the given cycle, the work done during isobaric process is:

A

200 J

B

Zero

C

400 J

D

600 J

Question 18: Palette 18/90

NEET 2023 MCQ

A container of volume $200 \mathrm{~cm}^3$ contains 0.2 mole of hydrogen gas and 0.3 mole of argon gas. The pressure of the system at temperature $200 \mathrm{~K}$ ($\mathrm{R}=8.3 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}$) will be :-

A

$6.15 \times 10^5 \mathrm{~Pa}$

B

$6.15 \times 10^4 \mathrm{~Pa}$

C

$4.15 \times 10^5 \mathrm{~Pa}$

D

$4.15 \times 10^6 \mathrm{~Pa}$

Question 19: Palette 19/90

NEET 2023 MCQ

The temperature of a gas is $-50^{\circ} \mathrm{C}$. To what temperature the gas should be heated so that the rms speed is increased by $3$ times?

A

$3295^{\circ} \mathrm{C}$

B

$3097 \mathrm{~K}$

C

$223 \mathrm{~K}$

D

$669^{\circ} \mathrm{C}$

Question 20: Palette 20/90

NEET 2023 MCQ

A Carnot engine has an efficiency of $50 \%$ when its source is at a temperature $327^{\circ} \mathrm{C}$. The temperature of the sink is :-

A

$15^{\circ} \mathrm{C}$

B

$100^{\circ} \mathrm{C}$

C

$200^{\circ} \mathrm{C}$

D

$27^{\circ} \mathrm{C}$

Question 21: Palette 21/90

NEET 2022 MCQ

An ideal gas follows a process described by the equation $P{V^2} = C$ from the initial $({P_1},\,{V_1},\,{T_1})$ to final $({P_2},\,{V_2},\,{T_2})$ thermodynamic states, where C is a constant. Then

A

If ${P_1} > {P_2}$ then ${V_1} > {V_2}$

B

If ${P_1} > {P_2}$ then ${T_1} < {T_2}$

C

If ${V_2} > {V_1}$ then ${T_2} > {T_1}$

D

If ${V_2} > {V_1}$ then ${T_2} < {T_1}$

Question 22: Palette 22/90

NEET 2022 MCQ

Two rods one made of copper and other made of steel of same length and same cross sectional area are joined together. The thermal conductivity of copper and steel are 385 J s^$-$1 K^$-$1 m^$-$1 and 50 J s^$-$1 K^$-$1 m^$-$1 respectively. The free ends of copper and steel are held at 100$^\circ$C and 0$^\circ$C respectively. The temperature at the junction is, nearly :

A

$88.5^\circ C$

B

$12^\circ C$

C

$50^\circ C$

D

$73^\circ C$

Question 23: Palette 23/90

NEET 2022 MCQ

Three vessels of equal capacity have gases at the same temperature and pressure. The first vessel contains helium (monoatomic), the second contains fluorine (diatomic) and the third contains sulfur hexafluoride (polyatomic). The correct statement, among the following is :

A

The root mean square speed of sulfur hexafluoride is the largest

B

All vessels contain unequal number of respective molecules

C

The root mean square speed of molecules is same in all three cases

D

The root mean square speed of helium is the largest

Question 24: Palette 24/90

NEET 2022 MCQ

An ideal gas undergoes four different processes from the same initial state as shown in the figure below. Those processes are adiabatic, isothermal, isobaric and isochoric. The curve which represents the adiabatic process among 1, 2, 3 and 4 is

A

1

B

2

C

3

D

4

Question 25: Palette 25/90

NEET 2022 MCQ

The volume occupied by the molecules contained in 4.5 kg water at STP, if the intermolecular forces vanish away is

A

5.6 $\times$ 10⁶ m³

B

5.6 $\times$ 10³ m³

C

5.6 $\times$ 10^$-$3 m³

D

5.6 m³

Question 26: Palette 26/90

NEET 2021 MCQ

A cup of coffee cools from 90$^\circ$C to 80$^\circ$C in t minutes, when the room temperature is 20$^\circ$C. The time taken by a similar cup of coffee to cool from 80$^\circ$C to 60$^\circ$C at a room temperature same at 20$^\circ$C is :

A

${5 \over {13}}$t

B

${13 \over {10}}$t

C

${13 \over {5}}$t

D

${10 \over {13}}$t

Question 27: Palette 27/90

NEET 2021 MCQ

Match Column - I and Column - II and choose the correct match from the given choices.

	Column - I		Column - II
(A)	Root mean square speed of gas molecules	(P)	${1 \over 3}nm{\overline v ^2}$
(B)	Pressure exerted by ideal gas	(Q)	$\sqrt {{{3RT} \over M}} $
(C)	Average kinetic energy of a molecule	(R)	${5 \over 2}RT$
(D)	Total internal energy of 1 mole of a diatomic gas	(S)	${3 \over 2}{k_B}T$

A

(A) - (R), (B) - (Q), (C) - (P), (D) - (S)

B

(A) - (R), (B) - (P), (C) - (S), (D) - (Q)

C

(A) - (Q), (B) - (R), (C) - (S), (D) - (P)

D

(A) - (Q), (B) - (P), (C) - (S), (D) - (R)

Question 28: Palette 28/90

NEET 2020 MCQ

The average thermal energy for a mono-atomic gas is : (k_B is Boltzmann constant and T absolute temperature)

A

${3 \over 2}{k_B}T$

B

${5 \over 2}{k_B}T$

C

${7 \over 2}{k_B}T$

D

${1 \over 2}{k_B}T$

Question 29: Palette 29/90

NEET 2020 MCQ

The mean free path for a gas, with molecular diameter d and number density n can be expressed as :

A

${1 \over {\sqrt 2 n\pi {d^2}}}$

B

${1 \over {\sqrt 2 {n^2}\pi {d^2}}}$

C

${1 \over {\sqrt 2 {n^2}{\pi ^2}{d^2}}}$

D

${1 \over {\sqrt 2 n\pi d}}$

Question 30: Palette 30/90

NEET 2020 MCQ

A cylinder contains hydrogen gas at pressure 249 kPa and temperature 27$^\circ $C
Its density is : (R = 8.3 J mol^-1 K^-1)

A

0.2 kg/m³

B

0.1 kg/m³

C

0.02 kg/m³

D

0.5 kg/m³

Question 31: Palette 31/90

NEET 2020 MCQ

The quantities of heat required to raise the temperature of two solid copper spheres of radii r₁ and r₂ (r₁ = 1.5r₂) through 1 K are in the ratio :

A

${9 \over 4}$

B

${3 \over 2}$

C

${5 \over 3}$

D

${27 \over 8}$

Question 32: Palette 32/90

NEET 2020 MCQ

Two cylinders A and B of equal capacity are connected to each other via a stop cock. A contains an ideal gas at standard temperature and pressure. B is completely evacuated. The entire systems is thermally insulated. The stop cock is suddenly opened. The Process is :

A

adiabatic

B

isochoric

C

isobaric

D

isothermal

Question 33: Palette 33/90

NEET 2019 MCQ

In which of the following processes, heat is neither absorbed nor released by a system?

A

adiabatic

B

isobaric

C

isochoric

D

isothermal

Question 34: Palette 34/90

NEET 2019 MCQ

Increase in tempertaure of a gas filled in a container would lead to :

A

increase in its kinetic energy

B

decrease in intermolecular distance

C

decrease in its pressure

D

increase in its mass

Question 35: Palette 35/90

NEET 2018 MCQ

At what temperature will the rms speed of oxygen molecules become just sufficient for escaping from the Earth’s atmosphere?
(Given : Mass of oxygen molecule (m) = 2.76 × 10^–26 kg, Boltzmann’s constant k_B = 1.38 × 10^–23 J K^–1)

A

2.508 × 10⁴ K

B

8.360 × 10⁴ K

C

5.016 × 10⁴ K

D

1.254 × 10⁴ K

Question 36: Palette 36/90

NEET 2018 MCQ

A sample of 0.1 g of water at 100°C and normal pressure (1.013 × 10⁵ N m^–2) requires 54 cal of heat energy to convert to steam at 100°C. If the volume of the steam produced is 167.1 cc, the change in internal energy of the sample, is

A

104.3 J

B

208.7 J

C

42.2 J

D

84.5 J

Question 37: Palette 37/90

NEET 2018 MCQ

The efficiency of an ideal heat engine working between the freezing point and boiling point of water, is

A

26.8%

B

20%

C

6.25%

D

12.5%

Question 38: Palette 38/90

NEET 2018 MCQ

The volume (V) of a monatomic gas varies with its temperature (T), as shown in the graph. The ratio of work done by the gas, to the heat absorbed by it, when it undergoes a change from state A to state B, is

A

${2 \over 5}$

B

${2 \over 3}$

C

${1 \over 3}$

D

${2 \over 7}$

Question 39: Palette 39/90

NEET 2017 MCQ

Thermodynamic processes are indicated in the following diagram.


Match the following

Column-1			Column-2
P.	Process I		A.	Adiabatic
Q.	Process II		B.	Isobaric
R.	Process III		C.	Isochoric
S.	Process IV		D.	Isothermal

A

P $ \to $ C,  Q $ \to $ A,  R $ \to $ D,   S $ \to $ B

B

P $ \to $ C,  Q $ \to $ D,  R $ \to $ B,   S $ \to $ A

C

P $ \to $ D,  Q $ \to $ B,  R $ \to $ A,   S $ \to $ C

D

P $ \to $ A,  Q $ \to $ C,  R $ \to $ D,   S $ \to $ B

Question 40: Palette 40/90

NEET 2017 MCQ

A gas mixture consists of 2 moles of O₂ and 4 moles of Ar at temperature T. Neglecting all vibrational modes, the total internal energy of the system is

A

15 RT

B

9 RT

C

11 RT

D

4 RT

Question 41: Palette 41/90

NEET 2017 MCQ

A carnot engine having an efficiency of ${1 \over {10}}$ 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

99 J

C

100 J

D

1 J

Question 42: Palette 42/90

NEET 2016 MCQ

One mole of an ideal monatomic gas undergoes a process described by the equation PV³ = constant. The heat capacity of the gas during this process is

A

${3 \over 2}$ R

B

${5 \over 2}$ R

C

2R

D

R

Question 43: Palette 43/90

NEET 2016 MCQ

The temperature inside a refrigerator is t₂ ^oC. The amount of heat delivered to the room for each joule of electrical energy consumed ideally will be

A

${{{t_1}} \over {{t_1} - {t_2}}}$

B

${{{t_1} + 273} \over {{t_1} - {t_2}}}$

C

${{{t_2} + 273} \over {{t_1} - {t_2}}}$

D

${{{t_1} + {t_2}} \over {{t_1} + 273}}$

Question 44: Palette 44/90

NEET 2016 MCQ

A given sample of an ideal gas occupies a volume V at a pressure P and absolute temperature T. The mass of each molecule of the gas is m. Which of the following gives the density of the gas ?

A

P/(kT)

B

Pm/(kT)

C

P/(KTV)

D

mkT

Question 45: Palette 45/90

NEET 2016 MCQ

A refrigerator works between 4^oC and 30^oC. It is required to remove 600 calories of heat every second in order to keep the temperature of the refrigerated space constant. The power required is (Take 1 cal = 4.2 Joules)

A

236.5 W

B

2365 W

C

2.365 W

D

23.65 W

Question 46: Palette 46/90

NEET 2016 MCQ

A gas is compressed isothermally to half its initial volume. The same gas is compressed separately through an adiabatic process until its volume is again reduced to half. Then

A

Compressing the gas isothermally or adiabatically will require the same amount of work.

B

Which of the case (whether compression through isothermal or through adiabatic process) requires more work will depend upon the atomicity of the gas.

C

Compressing the gas isothermally will require more work to be done.

D

Compressing the gas through adiabatic process will require more work to be done.

Question 47: Palette 47/90

NEET 2016 MCQ

The molecules of a given mass of a gas have r.m.s. velocity of 2000 m s^$-$1 at 27^oC and 1.0 $ \times $ 10⁵ N m^$-$2 pressure. When the temperature and pressure of the gas are respectively, 127^oC and 0.05 $ \times $ 10⁵ N m^$-$2, the r.m.s. velocity of its molecules in m s^$-$1 is

A

${{100\sqrt 2 } \over 3}$

B

${{100} \over 3}$

C

$100\sqrt 2 $

D

${{400} \over {\sqrt 3 }}$

Question 48: Palette 48/90

NEET 2015 MCQ

An ideal gas is compressed to half its initial volume by means of several processes. Which of the process results in the maximum work done on the gas ?

A

Isochoric

B

Isothermal

C

Adiabatic

D

Isobaric

Question 49: Palette 49/90

NEET 2015 MCQ

Two vessels separately contain two ideal gases A and B at the same temperature, the pressure of A being twice that of B. Under such conditions, the density of A is found to be 1.5 times the density of B. The ratio of molecular weight of A and B is

A

2

B

${1 \over 2}$

C

${2 \over 3}$

D

${3 \over 4}$

Question 50: Palette 50/90

NEET 2015 MCQ

The coefficient of performance of a refrigerator is 5. If the temperature inside freezer is $-$20^oC, the temperature of the surroundings to which it rejects heat is

A

11^oC

B

21^oC

C

31^oC

D

41^oC

Question 51: Palette 51/90

NEET 2015 MCQ

One mole of an ideal diatomic gas undergoes a transition from A to B along a path AB as shown in the figure.



The change in internal energy of the gas during the transition is

A

20 J

B

$-$ 12 kJ

C

20 kJ

D

$-$ 20 kJ

Question 52: Palette 52/90

NEET 2015 MCQ

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

Question 53: Palette 53/90

NEET 2015 MCQ

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

$\left( {1 + {n \over 3}} \right)$

Question 54: Palette 54/90

NEET 2015 MCQ

Figure below shows two paths that may be taken by a gas to go from a state A to a state C.


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

Question 55: Palette 55/90

NEET 2014 MCQ

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

Question 56: Palette 56/90

NEET 2014 MCQ

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

Question 57: Palette 57/90

NEET 2014 MCQ

The mean free path of molecules of a gas, (radius r) is inversely proportional to

A

r³

B

r²

C

r

D

$\sqrt r $

Question 58: Palette 58/90

NEET 2013 MCQ

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

Question 59: Palette 59/90

NEET 2013 MCQ

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

Question 60: Palette 60/90

NEET 2013 MCQ

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

${{{T_1} + {T_2}} \over 2}$

Question 61: Palette 61/90

NEET 2013 MCQ

Which of the following relations does not give the equation of an adiabatic process, where terms have their usual meaning?

A

P^{1$-$$\gamma $} T^{$\gamma $}  =  constant

B

PV^{$\gamma $}   =  constant

C

TV^{$\gamma $$-$1}  =  constant

D

P^{$\gamma $}  T^{1$-$$\gamma $}  =  constant

Question 62: Palette 62/90

NEET 2013 MCQ

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

Question 63: Palette 63/90

NEET 2013 MCQ

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

Zero

B

$-$ 2000 J

C

2000 J

D

1000 J

Question 64: Palette 64/90

NEET 2013 MCQ

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

${3 \over 2}{N_a}{k_B}\left( {{T_2} - {T_1}} \right)$

Question 65: Palette 65/90

NEET 2013 MCQ

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

Question 66: Palette 66/90

NEET 2012 MCQ

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

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

Question 67: Palette 67/90

NEET 2012 MCQ

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

Question 68: Palette 68/90

NEET 2012 MCQ

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

Question 69: Palette 69/90

NEET 2011 MCQ

A mass of diatomic gas $(\gamma = 1.4)$ at a pressure of 2 atmospheres is compressed adiabatically so that its temperature rises from 27^oC to 927^oC. The pressure of the gas in the final state is

A

8 atm

B

28 atm

C

68.7 atm

D

256 atm

Question 70: Palette 70/90

NEET 2011 MCQ

When 1 kg of ice at 0^oC melts to water at 0^oC, 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

Question 71: Palette 71/90

NEET 2011 MCQ

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

Question 72: Palette 72/90

NEET 2010 MCQ

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

Question 73: Palette 73/90

NEET 2010 MCQ

If c_p and c_v denote the specific heats (per unit mass of an ideal gas of molecular weight M, then

A

c_p $-$ c_v = R/M²

B

c_p $-$ c_v = R

C

c_p $-$ c_v = R/M

D

c_p $-$ c_v = MR

Question 74: Palette 74/90

NEET 2010 MCQ

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

Question 75: Palette 75/90

NEET 2009 MCQ

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

Question 76: Palette 76/90

NEET 2009 MCQ

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.

Question 77: Palette 77/90

NEET 2008 MCQ

At 10^oC the value of the density of a fixed mass of an ideal gas divided by it pressure is x. At 110^oC this ratio is

A

${{10} \over {110}}x$

B

${{283} \over {383}}x$

C

$x$

D

${{383} \over {283}}x$

Question 78: Palette 78/90

NEET 2008 MCQ

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

Question 79: Palette 79/90

NEET 2007 MCQ

An engine has an efficiency of 1/6. When the temperature of sink is reduced by 62^oC, its efficiency is doubled. Temperatures of the source is

A

37^oC

B

62^oC

C

99^oC

D

124^oC.

Question 80: Palette 80/90

NEET 2006 MCQ

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

Question 81: Palette 81/90

NEET 2006 MCQ

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

Question 82: Palette 82/90

NEET 2005 MCQ

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.

Question 83: Palette 83/90

NEET 2005 MCQ

An ideal gas heat engine operates in Carnot cycle between 227^oC and 127^oC. 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.

Question 84: Palette 84/90

NEET 2004 MCQ

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

Question 85: Palette 85/90

NEET 2004 MCQ

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

Question 86: Palette 86/90

NEET 2003 MCQ

An ideal gas heat engine operates in a Carnot cycle between 227^oC and 127^oC. 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

Question 87: Palette 87/90

NEET 2002 MCQ

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

Question 88: Palette 88/90

NEET 2001 MCQ

A scientist says that the efficiency of his heat engine which work at source temperature 127^oC and sink temperature 27^oC is 26%, then

A

it is impossible

B

it is possible but less probable

C

it is quite probable

D

data are incomplete.

Question 89: Palette 89/90

NEET 2000 MCQ

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

$f = {1 \over {\gamma + 1}}$

Question 90: Palette 90/90

NEET 2000 MCQ

The (W/Q) of a Carnot engine is 1/6, now the temperature of sink is reduced by 62^oC, then this ratio becomes twice, therefore the initial temperature of the sink and source are respectively

A

33^oC, 67^oC

B

37^oC, 99^oC

C

67^oC, 33^oC

D

97 K, 37 K