For the $P-V$ diagram given for an ideal gas,which of the following correctly represents the $T-P$ diagram?

Heat is given to an ideal gas in an isothermal process.
$A.$ Internal energy of the gas will decrease.
$B.$ Internal energy of the gas will increase.
$C.$ Internal energy of the gas will not change.
$D.$ The gas will do positive work.
$E.$ The gas will do negative work.
Choose the correct answer from the options given below:

The work done to increase the volume of $2$ moles of an ideal gas from $V$ to $2V$ at a constant temperature $T$ is $W$. The work to be done to increase the volume of $2$ moles of the same gas from $2V$ to $4V$ at the same constant temperature $T$ is:

Which of the accompanying $PV$ diagrams best represents an isothermal process?

During an isothermal expansion of an ideal gas,

For an ideal gas, in an isothermal process: