NEET Physics Thermodynamics Questions Solved


Carbon monoxide is carried around a closed cycle abc in which bc is an isothermal process as shown in the figure. The gas absorbs 7000 J of heat as its temperature increases from 300 K to 1000 K in going from a to b. The quantity of heat rejected by the gas during the process ca is -

(1) 4200 J

(2) 5000 J

(3) 9000 J

(4) 9800 J

(4) For path ab : (ΔU)ab=7000J

By using ΔU=μCVΔT

7000=μ×52R×700μ=0.48

For path ca :

(ΔQ)ca=(ΔU)ca+(ΔW)ca ….(i)

(ΔU)ab+(ΔU)bc+(ΔU)ca=0

7000+0+(ΔU)ca=0(ΔU)ca=7000J ….(ii)

Also (ΔW)ca=P1(V1V2)=μR(T1T2)

=0.48×8.31×(3001000)=2792.16J ….(iii)

on solving equations (i), (ii) and (iii)

(ΔQ)ca=70002792.16=9792.16J = –9800 J

Difficulty Level:

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