A closed hollow insulated cylinder is filled with gas at 0oC and also contains an insulated piston of negligible weight and negligible thickness at the middle point. The gas on one side is heated to 100oC. If the piston moves through 5 cm, the length of the hollow cylinder is
64.6 cm
Let L be the length (in cm) of the follow cylinder and r its radius. Since the mass of the gas remains unchanged and the pressures of the gas in both sides are equal, we have, from Charles' law,
V1T1=V2T2 ......(1)Given V1=(L2−5)πr2, V2=(L2+5)πr2, T1=0oC=273 K and T2=100oC=373 K. Using these values in (1), we get
L2−5273=L2+5373
which gives L = 64.6 cm.