What is the value of the specific heat of a gas during an isothermal process?

The isothermal elasticity of a gas is equal to

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

$Assertion :$ The isothermal curves intersect each other at a certain point.
$Reason :$ The isothermal changes take place rapidly,so the isothermal curves have very little slope.

Write the first law of thermodynamics for an isothermal process in an ideal gas.

The work done by an ideal gas of $2 \text{ moles}$ in increasing its volume from $V$ to $2V$ at constant temperature $T$ is $W$. The work done by an ideal gas of $4 \text{ moles}$ in increasing its volume from $V$ to $8V$ at constant temperature $\frac{T}{2}$ is: