A sample of an ideal gas is taken through the cyclic process ABCA as shown in figure below. It absorbs 60 J of heat during the part AB and rejects 80 J of heat during CA . There is no heat exchanged during the process $\mathrm{BC} . \mathrm{A}$ work of 40 J is done on the gas during the part BC . If the internal energy of the gas at A is 1450 J , then the work done by the gas during the part CA is:

The coefficient of volume expansion of glycerine is $$49 \times 10^{-5} \mathrm{~K}^{-1}$$. The percentage change in its density for a $$50^{\circ} \mathrm{C}$$ rise in temperature is