1
JEE Main 2022 (Online) 24th June Evening Shift
+4
-1
Out of Syllabus

A Carnot engine takes 5000 kcal of heat from a reservoir at 727$$^\circ$$C and gives heat to a sink at 127$$^\circ$$C. The work done by the engine is

A
3 $$\times$$ 106 J
B
Zero
C
12.6 $$\times$$ 106 J
D
8.4 $$\times$$ 106 J
2
JEE Main 2022 (Online) 24th June Evening Shift
+4
-1

A 100 g of iron nail is hit by a 1.5 kg hammer striking at a velocity of 60 ms$$-$$1. What will be the rise in the temperature of the nail if one fourth of energy of the hammer goes into heating the nail?

[Specific heat capacity of iron = 0.42 Jg$$-$$1 $$^\circ$$C$$-$$1]

A
675$$^\circ$$C
B
1600$$^\circ$$C
C
16.07$$^\circ$$C
D
6.75$$^\circ$$C
3
JEE Main 2022 (Online) 24th June Morning Shift
+4
-1
Out of Syllabus

A Carnot engine whose heat sinks at 27$$^\circ$$C, has an efficiency of 25%. By how many degrees should the temperature of the source be changed to increase the efficiency by 100% of the original efficiency?

A
Increases by 18$$^\circ$$C
B
Increases by 200$$^\circ$$C
C
Increases by 120$$^\circ$$C
D
Increases by 73$$^\circ$$C
4
JEE Main 2022 (Online) 24th June Morning Shift
+4
-1

Two metallic blocks M1 and M2 of same area of cross-section are connected to each other (as shown in figure). If the thermal conductivity of M2 is K then the thermal conductivity of M1 will be :

A
10 K
B
8 K
C
12.5 K
D
2 K
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