$2 \ mol$ of zinc is dissolved in $HCl$ at $25 \ ^\circ C$. The work done in an open vessel is:

If $\tan \theta + \cot \theta = 2$,then $\sin \theta$ is equal to

$A$ narrow parallel beam of light is incident paraxially on a solid transparent sphere of radius $r$ kept in air. What should be the refractive index if the beam is to be focused at the farther surface of the sphere?

Which is the major state producing Basmati rice in India?

The major product in the following reaction is:

Two capillary tubes of same diameter are put vertically one each in two liquids whose relative densities are $0.8$ and $0.6$ and surface tensions are $60$ and $50 \, dyne/cm$ respectively. The ratio of the heights of the liquids in the two tubes $\frac{h_1}{h_2}$ is: