$Mg$ is obtained by:

Which one of the following orders is correct for the bond dissociation energies of halogen molecules?

Two particles $P$ and $Q$ start from the origin and execute Simple Harmonic Motion along the $X$-axis with the same amplitude but with periods $3 \ s$ and $6 \ s$ respectively. The ratio of the velocities of $P$ and $Q$ when they meet is

$A$ rotating body has angular momentum $L$. If its frequency of rotation is halved and its rotational kinetic energy is doubled,what will be its new angular momentum?

The hydride ion $H^-$ is a stronger base than the hydroxide ion $OH^-$. If sodium hydride $(NaH)$ is dissolved in water,which of the following reactions will occur?

If $\sin ^{-1}\left(\frac{3}{x}\right)+\sin ^{-1}\left(\frac{4}{x}\right)=\frac{\pi}{2}$,then $x$ is equal to