JEE Main 2021 (Online) 27th July Morning Shift | Heat and Thermodynamics Question 109 | Physics

JEE Main 2021 (Online) 27th July Morning Shift

MCQ (Single Correct Answer)

-1

The number of molecules in one litre of an ideal gas at 300 K and 2 atmospheric pressure with mean kinetic energy 2 $$\times$$ 10^$$-$$9 J per molecules is :

0.75 $$\times$$ 10¹¹

3 $$\times$$ 10¹¹

1.5 $$\times$$ 10¹¹

6 $$\times$$ 10¹¹

JEE Main 2021 (Online) 27th July Morning Shift

MCQ (Single Correct Answer)

-1

In the reported figure, there is a cyclic process ABCDA on a sample of 1 mol of a diatomic gas. The temperature of the gas during the process A $$\to$$ B and C $$\to$$ D are T₁ and T₂ (T₁ > T₂) respectively.

JEE Main 2021 (Online) 27th July Morning Shift Physics - Heat and Thermodynamics Question 110 English

JEE Main 2021 (Online) 27th July Morning Shift Physics - Heat and Thermodynamics Question 110 English

Choose the correct option out of the following for work done if processes BC and DA are adiabatic.

W_AB = W_DC

W_AD = W_BC

W_BC + W_DA > 0

W_AB < W_CD

JEE Main 2021 (Online) 27th July Morning Shift

MCQ (Single Correct Answer)

-1

A body takes 4 min. to cool from 61$$^\circ$$ C to 59$$^\circ$$ C. If the temperature of the surroundings is 30$$^\circ$$ C, the time taken by the body to cool from 51$$^\circ$$ C to 49$$^\circ$$ C is :

4 min.

3 min.

8 min.

6 min.

JEE Main 2021 (Online) 25th July Evening Shift

MCQ (Single Correct Answer)

-1

A heat engine has an efficiency of $${1 \over 6}$$. When the temperature of sink is reduced by 62$$^\circ$$C, its efficiency get doubled. The temperature of the source is :

124$$^\circ$$C

37$$^\circ$$C

62$$^\circ$$C

99$$^\circ$$C

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