In an adiabatic expansion of air (assume it a mixture of `N_2` and `O_2`), the volume increases by `5%`. The percentage change in pressure is:

Options

A. `3%`
B. `4%`
C. `6%`
D. `7%`

Answer

D

Explanation

`PV^(gamma)=` constant
`P_(1)xx[(105 V)/100]^(gamma)=` constant
`:.(P_(1))/Pxx[105/100]^(gamma)=1`
or `(P_(1))/P=[100/105]^(gamma)`
or `(P_(1))/P=[100/105]^(7//5)`
`:. P_(1)=0.93 P`
`:. 7%` decrease in `P`.