70 calories of heat are required to raise the temperature of 2 moles of an ideal gas at constant pressure from 30°C to 35°C. The amount of heat required to raise the temperature of the same sample of the gas through the same range at constant volume is (Gas constant = 1.99 cal/K-mole)
(a) 30 cal
(b) 50 cal
(c) 70 cal
(d) 90 cal
