Question

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

• A. $\frac{2}{5}$
• B. $\frac{3}{5}$
• C. $\frac{3}{7}$
• D. $\frac{3}{4}$

Answer 1

Answer: (B)

$\frac{3}{5}$

Answer 2

For monatomic gas $\gamma=\frac{C_{p}}{C_{V}}=\frac{5}{3}$ We know that $Q =\mu C_{p} \Delta T$ and $\Delta U =\mu C_{V} \Delta T$ $\frac{\Delta U}{\Delta Q} =\frac{C_{V}}{C_{p}}=\frac{3}{5}$ ie, fraction of heat energy to increate the internal energy be $\frac{3}{5}$.