When an ideal diatomic gas is heated at constant pressure, the fraction of the heat energy supplied which increases the internal energy of the gas, is

In the $p-V$ diagram below, the dashed curved line is an adiabat.For a process that is described by a straight line joining two points $X$ and $Y$ on the adiabat (solid line in the diagram) heat is (Hint consider the variation in temperature from $X$ to $Y$ along the straight line)

An ideal gas expands from volume $V_1$ to $V_2$. This may be achieved by either of the three processes: isobaric, isothermal and adiabatic. Let $\Delta U$ be the change in internal energy of the gas, $Q$ be the quantity of heat added to the system and $W$ be the work done by the system on the gas. Identify which of the following statements is false for $\Delta U$?

Air is pumped into a balloon, of initial volume $V$ , until its diameter has doubled. If the atmospheric pressure is $p$ , what is the work done against the atmosphere ? 

In a cyclic process, work done by the system is