1
JEE Main 2019 (Online) 10th April Morning Slot
+4
-1
A cylinder with fixed capacity of 67.2 lit contains helium gas at STP. The amount of heat needed to raise the temperature of the gas by 20°C is : [Given that R = 8.31 J mol–1 K–1]
A
374 J
B
700 J
C
748 J
D
350 J
2
JEE Main 2019 (Online) 10th April Morning Slot
+4
-1
n moles of an ideal gas with constant volume heat capcity CV undergo an isobaric expansion by certain volume. The ratio of the work done in the process, to the heat supplied is :
A
$${{nR} \over {{C_V} - nR}}$$
B
$${{4nR} \over {{C_V} - nR}}$$
C
$${{4nR} \over {{C_V} + nR}}$$
D
$${{nR} \over {{C_V} + nR}}$$
3
JEE Main 2019 (Online) 10th April Morning Slot
+4
-1
A 25 × 10–3 m3 volume cylinder is filled with 1 mol of O2 gas at room temperature (300K). The molecular diameter of O2, and its root mean square speed, are found to be 0.3 nm, and 200 m/s, respectively. What is the average collision rate (per second) for an O2 molecule ?
A
~1013
B
~1012
C
~1011
D
~1010
4
JEE Main 2019 (Online) 9th April Evening Slot
+4
-1
50 W/m2 energy density of sunlight is normally incident on the surface of a solar panel. Some part of incident energy (25%) is reflected from the surface and the rest is absorbed. The force exerted on 1m2 surface area will be close to (c = 3 × 108 m/s) :-
A
20 × 10–8 N
B
35 × 10–8 N
C
10 × 10–8 N
D
15 × 10–8 N
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