Question

An ideal monoatomic gas undergoes the process AB as shown in the figure. If the heat supplied and the work done in the process are $\Delta Q$ and W respectively. The ratio $\Delta Q:W$ is

• A. 2.5
• B. 1.67
• C. 0.67
• D. 0.4

Answer 1

The correct option is A 2.5

For a diatomic gas:

$C_P=\frac{7}{2}R,C_V=\frac{5}{2}R$

The heat input is given by:

$\Delta Q=n{C}_V\Delta T=n\times \frac{5}{2}R\times \Delta T$

Work done is given by:

$\Delta W=\Delta Q-\Delta U$

$\Delta W=n\times \frac{7}{2}R\times \Delta T-n\times \frac{5}{2}R\times \Delta T=nR\Delta T$

Thus the ratio of $\Delta Q:W=5:2=2.5$