1
JEE Main 2021 (Online) 31st August Morning Shift
+4
-1
Out of Syllabus
A reversible engine has an efficiency of $${1 \over 4}$$. If the temperature of the sink is reduced by 58$$^\circ$$C, its efficiency becomes double. Calculate the temperature of the sink :
A
174$$^\circ$$C
B
280$$^\circ$$C
C
180.4$$^\circ$$C
D
382$$^\circ$$C
2
JEE Main 2021 (Online) 31st August Morning Shift
+4
-1
For an ideal gas the instantaneous change in pressure 'p' with volume 'v' is given by the equation $${{dp} \over {dv}} = - ap$$. If p = p0 at v =0 is the given boundary condition, then the maximum temperature one mole of gas can attain is : (Here R is the gas constant)
A
$${{{p_0}} \over {aeR}}$$
B
$${{a{p_0}} \over {eR}}$$
C
infinity
D
0$$^\circ$$C
3
JEE Main 2021 (Online) 27th August Evening Shift
+4
-1
if the rms speed of oxygen molecules at 0$$^\circ$$C is 160 m/s, find the rms speed of hydrogen molecules at 0$$^\circ$$C.
A
640 m/s
B
40 m/s
C
80 m/s
D
332 m/s
4
JEE Main 2021 (Online) 27th August Evening Shift
+4
-1
The height of victoria falls is 63 m. What is the difference in temperature of water at the top and at the bottom of fall?

[Given 1 cal = 4.2 J and specific heat of water = 1 cal g$$-$$1 $$^\circ$$0C$$-$$1]
A
0.147$$^\circ$$ C
B
14.76$$^\circ$$ C
C
1.476$$^\circ$$ C
D
0.014$$^\circ$$ C
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