The internal energy of an ideal gas increases during an isothermal process when the gas is

$Assertion :$ In an isothermal process,the whole of the heat supplied to the body is converted into internal energy.
$Reason :$ According to the first law of thermodynamics,$\Delta Q = \Delta U + P\Delta V$.

Two identical containers $A$ and $B$ with frictionless pistons contain the same ideal gas at the same temperature and same volume $V$. The mass of the gas in $A$ is $m_{A}$ and that in $B$ is $m_{B}$. The gas in each cylinder is now allowed to expand isothermally to the same final volume $2V$. The changes in the pressures of the gases in $A$ and $B$ are found to be $2\Delta P$ and $3\Delta P$ respectively. Then the relation between $m_{A}$ and $m_{B}$ is

If an ideal gas is compressed isothermally, which of the following statements is true?

An ideal gas is subjected to an isothermal expansion such that its volume changes from $V_i$ to $V_f$ and pressure from $P_i$ to $P_f$. The work done on the gas is:

When an ideal gas in a cylinder was compressed isothermally by a piston,the work done on the gas was found to be $1.5 \times 10^4 \ J$. During this process,about: