A sample of gas is compressed by an average pressure of $0.5\: atm$ so as to decrease its volume from $400 \: cm^3$ to $200\: cm^3$ . During the process $8\: J$ of heat flows out to surroundings. Calculate the change in internal energy of the system

Question

$\begin {array} {1 1} (A)\;-8 \: J & \quad (B)\;-2.13\: J \\ (C)\;2.13 \: J & \quad (D)\;18.13 \: J \end {array}$