When an ideal gas is heated at constant pressure,what percentage of the heat supplied is used to perform external work? $(\gamma = 5/3)$

Two identical samples of a gas are allowed to expand $(i)$ isothermally and $(ii)$ adiabatically. The work done is:

One mole of diatomic gas having rotational modes only is kept in a cylinder with a piston system. The cross-section area of the cylinder is $4 \text{ cm}^2$. The gas is heated slowly to raise the temperature by $1.2^\circ\text{C}$ during which the piston moves by $25 \text{ mm}$. The amount of heat supplied to the gas is . . . . . . $J$. (Atmospheric pressure = $100 \text{ kPa}$,$R = 8.3 \text{ J/mol}\cdot\text{K}$) (Neglect mass of the piston)

Carbon monoxide is taken around the closed cycle $abc$. The process $bc$ is isothermal as shown in the figure. When the temperature of the gas is increased from $300 \ K$ to $1000 \ K$,it absorbs $7000 \ J$ of heat in going from $a$ to $b$. The heat released by the gas during the process $ca$ is ...... $J$.

An ideal gas undergoes a cyclic process as shown in the density-pressure graph. During the process $AB$, the work done $|W_{AB}| = 70\,J$. During the process $BC$, the gas absorbs $150\,J$ of heat. During the process $CA$, the gas undergoes expansion and does $210\,J$ of work. Which of the following statements is correct?

An ideal gas with pressure $P$,volume $V$ and temperature $T$ is expanded isothermally to a volume $2V$ and a final pressure $P_i$. The same gas is expanded adiabatically to a volume $2V$,the final pressure is $P_a$. In terms of the ratio of the two specific heats for the gas $\gamma$,the ratio $\frac{P_i}{P_a}$ is