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CBSE-XI-Physics

27: Specific Heat Capacities of Gases

with Solutions -
Qstn# ii-3 Prvs-QstnNext-Qstn
  • #3
    The value of Cp - Cv is 1.00 R for a gas sample in state A and 1.08 R in state B. Let pA and pB denote the pressures and TA and TB denote the temperatures of the states A and B, respectively. It is most likely that
    (a) pA < pB and TA > TB
    (b) pA > pB and TA < TB
    (c) pA = pB and TA < TB
    (d) pA > pB and TA = TB
    digAnsr:   a
    Ans : (a) pA < pB and TA > TB
    Cp - Cv = R for the gas in state A, which means it is acting as an ideal gas in that state, whereas Cp - Cv = 1.08R in state B, i.e. the behaviour of the gas is that of a real gas in that state. To be an ideal gas, a real gas at STP should be at a very high temperature and low pressure. Therefore, PA < PB and TA > TB where PA and PB denotes the pressure and TA and TB denotes the temperature of system A and B reepectively.
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