The prssure in a monoatomic gas increases lineraly from `4 xx 10^(5) Nm^(-2) to 8 xx 10^(5)Nm^(-2)` when its volume increases form `0.2 m^(3) to 0.5 m^(3)`. Calculate the following:
(a) work done by the gas. (2) increase in the internal energy

Explanation

As her pressure is varying linearly with volume, work done by the gas
`Delta Q int PdV=` area under P-V curve which in the light of figure 1 becomes:
`Delta W = P_(1) (V_(F) -V_(1)) (P_(F) -P_(1)) xx (V_(F) -V_(1))`
i.e., `Delta W = P _(I ) (V_(F) -V_(1)) + 1/2 (P_(F) -P_(1)) xx (V_(F) -V_(1))`

i.e., `Delta W =1/2 (0.5 -0.2) (8+4) xx 10^(5)`
i.e., `Delta W =1.8 xx10^(5) J`