70 calories of heat required to raise the temperature of 2 moles of an ideal gas at constant pressure from `30^@Cto 35^@C.` The amount of heat required (in calories) to raise the temperature of the same gas through the same range `(30^@C to 35^@C)` at constant volume is:

Options

A. 30 cal
B. 50 cal
C. 70 cal
D. 90 cal

Answer

B

Explanation

`(DeltaQ)_P=nC_PDeltaT`
`70=2C_P(35-30)impliesC_P=7(cal)/(mol e^@C)`
`C_P-C_V=Rimplies7-C_V=2impliesC_V=5(cal)/(mol e^@C)`
`(DeltaQ)_V=nC_VDeltaT=2xx5xx(35-30)=50cal`