In an ellipse,the distance between its foci is $6$ and its minor axis is $8$. Then its eccentricity is

$CH_3 - C \equiv CH$ $\xrightarrow{Na} X$ $\xrightarrow{CH_3 - Cl} Y$,
$Y$ is

At $298 \ K$,the molar conductivities at infinite dilution $(\Lambda_m^{\circ})$ of $NH_4Cl$,$KOH$,and $KCl$ are $152.8$,$272.6$,and $149.8 \ S \ cm^2 \ mol^{-1}$ respectively. The $\Lambda_m^{\circ}$ of $NH_4OH$ in $S \ cm^2 \ mol^{-1}$ and $\%$ dissociation of $0.01 \ M \ NH_4OH$ with $\Lambda_m = 25.1 \ S \ cm^2 \ mol^{-1}$ at the same temperature are:

If $f(x) = \left| \begin{array}{ccc} 2 \cos x & 1 & 0 \\ x - \frac{\pi}{2} & 2 \cos x & 1 \\ 0 & 1 & 2 \cos x \end{array} \right|$,then $f^{\prime}(\pi)$ is equal to

$A$ bar magnet of magnetic moment $M$ and moment of inertia $I$ is freely suspended such that the magnetic axial line is in the direction of the magnetic meridian. If the magnet is displaced by a very small angle $\theta$,the angular acceleration is (Magnetic induction of earth's horizontal field $= B_H$)

In the figure, a potential of $+1200 \, V$ is applied to point $A$ and point $B$ is earthed. What is the potential at point $P$ (in $V$)?