Glauber's salt is

The kinetic energy of a particle executing $S.H.M.$ is $16 \ J$ when it is in its mean position. If the amplitude of oscillations is $25 \ cm$ and the mass of the particle is $5.12 \ kg$,the time period of its oscillation is

$A$ fan of moment of inertia $0.6 \, kg \cdot m^2$ is turned up to a working speed of $0.5$ revolutions per second. The angular momentum of the fan is:

The time in seconds required to produce a potential difference of $20 \ V$ across a capacitor of $1000 \ \mu F$ when it is charged at a steady rate of $200 \ \mu C/s$ is:

The equation of a plane containing the line of intersection of the planes $2x - y - 4 = 0$ and $y + 2z - 4 = 0$ and passing through the point $(1, 1, 0)$ is:

Four positive point charges $+q$ are kept at the four corners of a square of side $l$. The net electric field at the mid-point of any one side of the square is (Take,$\frac{1}{4 \pi \varepsilon_0}=k$)