Q.

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.                       [2013]

1 The rate at which heat is absorbed in the range 0–100 K varies linearly with temperature T.  
2 Heat absorbed in increasing the temperature from 0–100 K is less than the heat required for increasing the temperature from 400–500 K.  
3 There is no change in the rate of heat absorption in the range 400–500 K.  
4 The rate of heat absorption increases in the range 200–300 K.  

Ans.

(2, 3, 4)

(1)  As we know, Q=mcΔT

dQdt=mcdTdt  or,  dQdtC  i.e., rate of heat absorption C.

In the range 0 to 100K from the graph, C increases with temperature but not linearly therefore the rate at which heat is absorbed varies with temperature. But not linearly.

(2) As the value of C is greater in the temperature range 400-500K, the heat absorbed in increasing the temperature from 0-100K is less than the heat required for increasing the temperature from 400-500K.

(3) From the graph the value of C does not change in the temperature range 400-500K, therefore there is no change in the rate of heat absorption in this range.

(4) As the value of C increases from 200-300K, the rate of heat absorption increases in the range 200-300K.