JEE Advanced 2013 · Paper 2 · Physics Q3

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PhysicsMultiple correct+3 / -1Question 3 of 60

The figure below shows the variation of specific heat capacity ( $C$ ) of a solid as a function of temperature ( $T$ ). The temperature is increased continuously from 0 to 500 K at a constant rate. Ignoring any volume change, the following statement(s) is (are) correct to a reasonable approximation.

C against T (K) from 0 to 500 K: C rises from zero, roughly linearly at first, bends over around 150-250 K and levels off to a constant value (dashed asymptote) by about 400 K.

the rate at which heat is absorbed in the range 0-100 K varies linearly with temperature

T

heat absorbed in increasing the temperature from 0-100 K is less than the heat required for increasing the temperature from 400-500 K.

there is no change in the rate of heat absorption in the range 400-500 K.

the rate of heat absorption increases in the range 200-300 K.

Answer and worked solution

Official answer: A, B, C, D

Heating at a constant rate. The rate of heat absorption is $C\dfrac{dT}{dt}\propto C(T)$ .

(A) For 0-100 K the curve is nearly a straight line through the origin, so the rate grows roughly linearly with T. ✓ (approximately; the key also accepts BCD)
(B) $C$ is much smaller at low T, so less heat is needed for 0-100 K than for 400-500 K. ✓
(C) $C$ is constant for 400-500 K. ✓
(D) $C$ still rises between 200 and 300 K. ✓

(A), (B), (C), (D) (key: ABCD or BCD)

Topics:Calorimetry and specific heat

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JEE Advanced 2013 · Paper 2, Physics question 3