The substance used in the thermite process of reducing metal ores is

The equivalent mass of an element is $4$. Its chloride has a vapor density of $59.25$. What is the valency of the element?

We have two spheres,one of which is hollow and the other solid. They have identical masses and moments of inertia about their respective diameters. The ratio of their radii is given by

The synthesis of alkyl fluorides is best accomplished by:

$A$ pulley of radius $2\, m$ is rotated about its axis by a force $F = (20t - 5t^2)\, N$ (where $t$ is measured in seconds) applied tangentially. If the moment of inertia of the pulley about its axis of rotation is $10\, kg\, m^2$,the number of rotations made by the pulley before its direction of motion is reversed,is

If $\tan x + \tan \left(x + \frac{\pi}{3}\right) + \tan \left(x + \frac{2\pi}{3}\right) = 3$,then $\tan 3x$ is equal to