3 . Expansion of Gases There are two types of coefficient of expansion in gases
( i ) Volume Coefficient (& gamma ; v ) At constant pressure , the change in volume per unit volume per degree celsius is called volume coefficient .
where V0 , V1 , and V2 are volumes of the gas at 0 ° C , t1 ° C and t2 ° C .
( ii ) Pressure Coefficient ( γp ) At constant volume , the change in pressure per unit pressure per degree celsius is called pressure coefficient .
where p0 , p1 and p2 are pressure of the gas at 0 ° C , t1 ° C and t2 ° C . Practical Applications of Expansion
1 . When rails are laid down on the ground , space is left between the end of two rails .
2 . The transmission cables are not tightly fixed to the poles .
3 . The iron rim to be put on a cart wheel is always of slightly smaller diameter than that of wheel .
4 . A glass stopper jammed in the neck of a glass bottle can be taken out by warming the neck of the bottles .
Important Points
Due to increment in its time period a pendulum clock becomes slow in summer and will lose time .
Loss of time in a time period ΔT =( 1 / 2 ) α ΔθT ∴ Loss of time in any given time interval t can be given by ΔT =( 1 / 2 ) α Δθt