10 mole of an ideal gas is undergoing the process shown in the figure. The heat involved in the process from $P_1$ to $P_2$ is $\alpha$ Joule ( $P_1=21.7 \mathrm{~Pa}$ and $\left.P_2=30 \mathrm{~Pa}, \mathrm{C}_v=21 \mathrm{~J} / \mathrm{K} . \mathrm{mol}, R=8.3 \mathrm{~J} / \mathrm{mol} . \mathrm{K}\right)$. The value of $\alpha$ is $\_\_\_\_$ .

In a vernier callipers, 50 vernier scale divisions are equal to 48 main scale divisions. If one main scale division $=0.05 \mathrm{~mm}$, then the least count of the vernier callipers is $\_\_\_\_$ mm.

Five persons $P_1, P_2, P_3, P_4$ and $P_5$ recorded object distance $(u)$ and image distance (v) using same convex lens having power +5 D as $(25,96),(30,62),(35,37),(45,35)$ and $(50,32)$ respectively. Identify correct statement

The binding energy for the following nuclear reactions are expressed in MeV .

$$ \begin{aligned} & { }_2 \mathrm{He}^3+{ }_0 \mathrm{n}^1 \rightarrow{ }_2 \mathrm{He}^4+20 \mathrm{MeV} \\ & { }_2 \mathrm{He}^4+{ }_0 \mathrm{n}^1 \rightarrow{ }_2 \mathrm{He}^5-0.9 \mathrm{MeV} \end{aligned} $$

If $\mathrm{X}_3, \mathrm{X}_4, \mathrm{X}_5$ denote the stability of ${ }_2 \mathrm{He}^3,{ }_2 \mathrm{He}^4$ and ${ }_2 \mathrm{He}^5$, respectively, then the correct order is :