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Thermodynamics

Question
CBSEENPH11026357

One mole of a monoatomic ideal gas undergoes the process A → B in the given p-V diagram. The molar heat capacity for this process is

          

  • 3R2

  • 13 R6

  • 5 R2

  • 2R

Solution

B.

13 R6

A pressure-volume ( or PV diagram or volume-pressure loop) is used to describe corresponding changes in volume and pressure in a system. They are commonly used in thermodynamics, cardiovascular physiology, and respiratory physiology.

WAB = Area under p-V diagram

          = 4 V0 × 3p0 + 12 4 V0 × 3 p0

         = 18 p0 V0

∴  ΔU = nCv ΔT

         = 1. 32 R TB -TA

         = 32R 30 p0 V0R - 3 p0 V0R

         = 812 p0 V0

Thus,  QAB = WAB + UAB

                       = 18 p0 V0 + 812 p0 V0

            QAB  = 1172p0 V0

Molar heat capacity

            C = Qn T

                = 117 p0 V0230 p0 V0R - 3 p0 V0R

               = 117 p0V0227 p0 V0R

        C = 13R6