Amongst $LiCl$,$RbCl$,$BeCl_{2}$,and $MgCl_{2}$,the compounds with the greatest and the least ionic character,respectively,are

The minimum distance of a point on the curve $y = x^2 - 4$ from the origin is

In a $P$-type semiconductor,germanium is doped with:

$\int \frac{1+\cos 4 x}{\cot x-\tan x} d x$ is equal to

If $\int \frac{d x}{x(\log x-2)(\log x-3)}=I+C$,then $I$ is equal to

Two coaxial solenoids are made by winding thin insulated wire over a pipe of cross-sectional area $A = 10 \, cm^2$ and length $\ell = 20 \, cm$. If one of the solenoids has $N_1 = 300$ turns and the other has $N_2 = 400$ turns,their mutual inductance is (given $\mu_0 = 4\pi \times 10^{-7} \, T \cdot m \cdot A^{-1}$):