AP and TS EAMCET Engineering 2020 Model Paper 1

If temperature volume and pressure of fixed amount (say n mole) of a gas vary
from T1,V1 and ρ1 to T2,V2 and ρ2 respectively. Then, ideal gas equation for two states can be written as
ρ1V1=nRT1 of

ρ1V1

T1

=nR ......(i)
ρ2V2=nRT2 of

ρ2V2

T2

=nR ......(ii)
on combining Eqs. (i) and (ii), we get

ρ1V1

T1

=

ρ2V2

T2

or

ρ1V1

ρ2V2

=

T1

T2

So, it called combined gas equation