Which of the following alkaline earth metal nitrides is volatile?

An atomic power nuclear reactor can deliver $300 \, MW$. The energy released due to the fission of each nucleus of uranium atom $U^{238}$ is $170 \, MeV$. The number of uranium atoms fissioned per hour will be:

$A$ body of mass $5 \ kg$ starts from the origin with an initial velocity $u = 30 \hat{i} + 40 \hat{j} \ ms^{-1}$. When a constant force $F = -(\hat{i} + 5 \hat{j}) \ N$ acts on the body,the time in which the $y$-component of the velocity becomes zero is (in $s$)

In a $500 \ mL$ flask,the degree of dissociation of $PCl_5$ at equilibrium is $40 \%$ and the initial amount is $5 \ moles$. The value of equilibrium constant in $mol \ L^{-1}$ for the decomposition of $PCl_5$ is

If $|a| = 2$,$|b| = 3$ and $a, b$ are mutually perpendicular,then the area of the triangle whose vertices are $0, a + b, a - b$ is

$A$ stationary wave is represented by $y = 10 \sin \frac{\pi x}{4} \cos 20 \pi t$,where $x$ and $y$ are expressed in $cm$ and $t$ in seconds. The distance between two consecutive nodes is: (in $cm$)