KCET 2021 Physics Solved Paper

Volume expansion is the expansion of volume of a gas due to increase in its temperature.
∴ Coefficient of volume expansion is given as
αV=

×V

V×ΔT

...(i)
where, V= real volume of gas,
ΔV= change in volumeand ΔT= change in temperature.
From ideal gas equation,
pV=nRT or T=

pV

nR

...(ii)
For constant pressure,
pΔV=nRΔT
or

ΔV

ΔT

=

nR

p

...(iii)
From Eqs. (i) and (iii), we get
αV=

nR

pV

=

1

T

[ ∵ From Eq. (ii)]
Thus, the variation of αV with temperature is correctly depicted in option (b).