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

$A$ very large number of balls are thrown vertically upwards in quick succession in such a way that the next ball is thrown when the previous one is at the maximum height. If the maximum height is $5 \, m$,the number of balls thrown per minute is (take $g = 10 \, m/s^2$).

$y=A e^x+B e^{2 x}+C e^{3 x}$ satisfies the differential equation

Match the corresponding entries of Column-$I$ with Column-$II$. (Where $m$ is the magnification produced by the mirror)

The vapour pressure in $mm$ of $Hg$,of an aqueous solution obtained by adding $18 \ g$ of glucose $(C_6H_{12}O_6)$ to $180 \ g$ of water at $100^{\circ} C$ is

$\int\left(\sqrt{\frac{a+x}{a-x}}+\sqrt{\frac{a-x}{a+x}}\right) d x$ is equal to