Get Dream IIT in Drop Year | Up to 70% OFF | Limited Seats

# Kinetic Theory of Gases - JEE Advanced Previous Year Questions with Solutions

JEE Advanced Previous Year Questions of Physics with Solutions are available at eSaral. Practicing JEE Advanced Previous Year Papers Questions of Physics will help the JEE aspirants in realizing the question pattern as well as help in analyzing weak & strong areas. Get detailed Class 11th & 12th Physics Notes to prepare for Boards as well as competitive exams like IIT JEE, NEET etc. eSaral helps the students in clearing and understanding each topic in a better way. eSaral is providing complete chapter-wise notes of Class 11th and 12th both for all subjects.       Download eSaral app  for free study material and video tutorials.   Simulator   Previous Years JEE Advanced Questions
Q. A real gas behaves like an ideal gas if its ? (A) pressure and temperature are both high (B) pressure and temperature are both low (C) pressure is high and temperature is low (D) pressure is low and temperature is high
Ans. (D) $\operatorname{High} \vec{P},$ Low $P$
Q. A mixture of 2 moles of helium gas (atomic mass = 4 amu) and 1 mole of argon gas (atomic mass = 40 amu) is kept at 300 K in a container. The ratio of the rms speeds $\left(\frac{v_{r m s}(\text {helium})}{v_{r m s}(\text {arg on})}\right)$ is ? (A) 0.32         (B) 0.45            (C) 2.24              (D) 3.16 [JEE-2012]
Ans. (D) $v_{m s}=\sqrt{\frac{3 R T}{M}} ; \frac{\left(v_{m s}\right)_{H e}}{\left(v_{m s}\right)_{A r}}=\sqrt{\frac{M_{A r}}{M_{H e}}}=\sqrt{\frac{40}{4}}=\sqrt{10}=3.16$
Q. Two non-reactive monoatomic ideal gases have their atomic masses in the ratio 2 : 3. The ratio of their partial pressures, when enclosed in a vessel kept at a constant temperature, is 4 : 3. The ratio of their densities is :- (A) 1 : 4          (B) 1 : 2           (C) 6 : 9            (D) 8 : 9 [JEE-2013]
Ans. (D) $\mathrm{P}=\frac{\rho}{\mathrm{M}} \mathrm{RT}$ $\Rightarrow \frac{\mathrm{P}_{1}}{\mathrm{P}_{2}}=\frac{\rho_{1} \mathrm{M}_{2}}{\rho_{2} \mathrm{M}_{1}}=\frac{4}{3} \Rightarrow \frac{\rho_{1}}{\rho_{2}}=\frac{4}{3} \times \frac{2}{3}=\frac{8}{9}$
Q. A container of fixed volume has a mixutre of one mole of hydrogen and one mole of helium in equilibrium at temperature T. Assuming the gases are ideal, the correct statement(s) is (are) :- (A) The average energy per mole of the gas mixture is 2RT. (B) The ratio of speed of sound in the gas mixture to that in helium gas is $\sqrt{6 / 5}$. (C) The ratio of the rms speed of helium atoms to that of hydrogen molecules is 1/2. (D) The ratio of the rms speed of helium atoms to that of hydrogen molecules is $1 / \sqrt{2}$. [JEE-Advance-2015]
Ans. (A,B,D) $C_{V(\operatorname{mix})}=\frac{(1)\left(\frac{3}{2} R\right)+(1)\left(\frac{5}{2} R\right)}{2}=2 R$ $\mathrm{C}_{\mathrm{P}(\mathrm{mix})}=3 \mathrm{R} \quad \gamma_{\operatorname{mix}}=\frac{3}{2} \Rightarrow \mathrm{f}=4$ Average energy/mole $=\mathrm{f} \frac{1}{2} \mathrm{RT}=2 \mathrm{RT}$ $\frac{\left(\mathrm{V}_{\mathrm{sound}}\right)_{\mathrm{mixture}}}{\left(\mathrm{V}_{\mathrm{sound}}\right)_{\mathrm{He}}}=\frac{\sqrt{\frac{\mathrm{RT}}{2}}}{\sqrt{\frac{5 \mathrm{RT}}{12}}}=\sqrt{\frac{6}{5}}$ $\frac{\left(\mathrm{V}_{\mathrm{rms}}\right)_{\mathrm{He}}}{\left(\mathrm{V}_{\mathrm{rms}}\right)_{\mathrm{H}_{2}}}=\frac{\sqrt{\frac{3 \mathrm{RT}}{4}}}{\sqrt{\frac{3 \mathrm{RT}}{2}}}=\frac{1}{\sqrt{2}}$ $\therefore(\mathrm{A}, \mathrm{B}, \mathrm{D})$

Rajat
Sept. 26, 2020, 8:35 a.m.
Thanks
Saranya
Sept. 25, 2020, 3:25 p.m.
Thanq so much sir