Nitrobenzene on reduction using zinc in alkaline medium results in $X$. The number of $\sigma$ and $\pi$ bonds in $X$ is

Laughing gas is prepared by heating

$10 \ g$ of hydrogen and $64 \ g$ of oxygen were filled in a steel vessel and exploded. The amount of water produced in this reaction will be ........... $mol$.

$A$ plane electromagnetic wave of wave intensity $6 \, W/m^2$ strikes a small mirror of area $40 \, cm^2$,held perpendicular to the approaching wave. The momentum transferred by the wave to the mirror each second will be:

For a transistor,the current amplification factor $\alpha$ is $0.8$. The transistor is connected in a common emitter configuration. The change in the collector current when the base current changes by $6 \, mA$ is ..... $mA$.

If ${}^n P_r = 30240$ and ${}^n C_r = 252$,then the ordered pair $(n, r)$ is equal to