1
JEE Main 2022 (Online) 25th July Evening Shift
+4
-1

Sound travels in a mixture of two moles of helium and n moles of hydrogen. If rms speed of gas molecules in the mixture is $$\sqrt2$$ times the speed of sound, then the value of n will be :

A
1
B
2
C
3
D
4
2
JEE Main 2022 (Online) 25th July Evening Shift
+4
-1

Let $$\eta_{1}$$ is the efficiency of an engine at $$T_{1}=447^{\circ} \mathrm{C}$$ and $$\mathrm{T}_{2}=147^{\circ} \mathrm{C}$$ while $$\eta_{2}$$ is the efficiency at $$\mathrm{T}_{1}=947^{\circ} \mathrm{C}$$ and $$\mathrm{T}_{2}=47^{\circ} \mathrm{C}$$ The ratio $$\frac{\eta_{1}}{\eta_{2}}$$ will be :

A
0.41
B
0.56
C
0.73
D
0.70
3
JEE Main 2022 (Online) 25th July Morning Shift
+4
-1

A certain amount of gas of volume $$\mathrm{V}$$ at $$27^{\circ} \mathrm{C}$$ temperature and pressure $$2 \times 10^{7} \mathrm{Nm}^{-2}$$ expands isothermally until its volume gets doubled. Later it expands adiabatically until its volume gets redoubled. The final pressure of the gas will be (Use $$\gamma=1.5)$$ :

A
$$3.536 \times 10^{5} \mathrm{~Pa}$$
B
$$3.536 \times 10^{6} \mathrm{~Pa}$$
C
$$1.25 \times 10^{6} \mathrm{~Pa}$$
D
$$1.25 \times 10^{5} \mathrm{~Pa}$$
4
JEE Main 2022 (Online) 25th July Morning Shift
+4
-1

Following statements are given :

(A) The average kinetic energy of a gas molecule decreases when the temperature is reduced.

(B) The average kinetic energy of a gas molecule increases with increase in pressure at constant temperature.

(C) The average kinetic energy of a gas molecule decreases with increase in volume.

(D) Pressure of a gas increases with increase in temperature at constant pressure.

(E) The volume of gas decreases with increase in temperature.

Choose the correct answer from the options given below :

A
(A) and (D) only
B
(A), (B) and (D) only
C
(B) and (D) only
D
(A), (B) and (E) only
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