Heat is given to an ideal gas in an isothermal process. Then

Can the temperature of a system remain constant even when it is heated? Explain.

Can the change in internal energy of an ideal gas be non-zero during an isothermal process?

In an isothermal expansion,what happens to the internal energy of the gas?

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:

$A$ sample of an ideal gas undergoes an isothermal expansion. If $dQ$,$dU$,and $dW$ represent the amount of heat supplied,the change in internal energy,and the work done respectively,then: