A gas under constant pressure of `4.5 xx 10^(5) Pa` when subjected to `800 kJ` of heat, changes the volume from `0.5 m^(3) to 2.0 m^(3)`. The change in internal energy of the gas is

Options

A. `6.75 xx 10^(5) J`
B. `5.25 xx 10^(5) J`
C. `3.25 xx 10^(5) J`
D. `1.25 xx 10^(5) J`

Answer

D

Explanation

`P = 4.5xx105 Pa , dQ = 800kJ`
`V_(1)=0.5m^3 , V_(2)= 2m^(3)`
`dW = P(V_(2)-V_(1)) = 4.5xx10^(5)(2xx0.5)`
`=6.75xx10^(5)J`
Change in internal energy
`dU = dQ-dW`
`=800xx10^(3)-6.75xx10^(5)`
`=1.25xx10^(5)J`.