6.Critical volume is :
(A) `V_(C)=3a`
(B) `V_(c)=3b`
(C) `V_(c)=3/b`
(D) `V_(c)=(27Rb)/(8a)`

Assertion: The numerical values of P_(c ), V_(c ) and T_(c ) are (a)/(27b^(2)), 3b and (8 a)/(27 Rb) respectively. Reason: The compressibility factor Z at critical conditions is 3//8

Find out following (i) V_(A)-V_(B) (ii) V_(B)-V_(C) (iii) V_(C)-V_(A) (iv) V_(D)-V_(C) (v) V_(A)-V_(D) (vi) Arrange the order of potential for points A, B, C and D.

A cycle followed by an engine (made of one mole of perfect gas in a cylinder with a piston) is shown in figure. A to B volume constant, B to C adiabatic, C to D volume constant and D to A adiabatic " "V_(C)=V_(D)=2V_(A) = 2V_(B) (a) In which part of the cycle heat is supplied to the engine form outside? (b) In which part of the cycle heat is being given to the surrounding by the engine ? (c ) What is the work done by the engine in one cycle ? Write your answer in term of p_(A),p_(B),V_(A) ? (d) What is the efficiency of the engine ? " "(gamma=(5)/(3) for the gas ) , (C_(V)= (3)/(2)R for one mole )