If the pressure of an ideal gas is decreased by $10 \%$ isothermally,then its volume will

The condition $dw = dq$ holds good in the following process:

In isothermal expansion,the pressure is determined by

$Assertion :$ 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.

$A$ gas is compressed at constant temperature. Its molecules gain:

$A$ 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?