JEE Main 2022 · 27 Jul · Shift 1 · Physics Q38

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PhysicsSingle correct+4 / -1Question 38 of 90

Read the following statements :

A. When small temperature difference between a liquid and its surrounding is doubled, the rate of loss of heat of the liquid becomes twice.

B. Two bodies P and Q having equal surface areas are maintained at temperature 10°C and 20°C. The thermal radiation emitted in a given time by P and Q are in the ratio 1:1.15.

C. A Carnot Engine working between 100K and 400K has an efficiency of 75%.

D. When small temperature difference between a liquid and its surrounding is quadrupled, the rate of loss of heat of the liquid becomes twice.

Choose the correct answer from the options given below :

A, B, C only

A, B only

A, C only

B, C, D only

Answer and worked solution

Official answer: A

A is true (Newton's law of cooling is linear in the difference), so D is false.

B is true: $\left(\frac{283}{293}\right)^4\approx\frac1{1.15}$ .

C is true: $1-\frac{100}{400}=75\%$ .

(A)

Topics:Newton's law of cooling Radiation and Stefan's law Carnot cycle

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JEE Main 2022 · 27 Jul · Shift 1, Physics question 38