What is the relationship between pressure $P$ and volume $V$ for an ideal gas undergoing an isothermal process?

$A$ vertical cylinder with heat-conducting walls is closed at the bottom and is fitted with a smooth light piston. It contains one mole of an ideal gas. The temperature of the gas is always equal to the surrounding's temperature,$T_0$. The piston is moved up slowly to increase the volume of the gas to $\eta$ times. Which of the following is incorrect?

$Assertion :$ The isothermal curves intersect each other at a certain point.
$Reason :$ The isothermal change takes place slowly,so,the isothermal curves have very little slope.

In an isothermal change,the change in pressure and volume of a gas can be represented for three different temperatures $T_3 > T_2 > T_1$ as:

The specific heat of a gas in an isothermal process is

During the isothermal expansion,a confined ideal gas does $(-150) \ J$ of work against its surroundings. This means that