In an $ac$ circuit $I = 100 \sin(200 \pi t)$. The time required for the current to achieve its peak value will be

When an unpolarized light of intensity $I_0$ is incident on a polarizing sheet,the intensity of the light which does not get transmitted is

Two concentric coils each of radius equal to $2\pi \, cm$ are placed at right angles to each other. $3\, A$ and $4\, A$ are the currents flowing in each coil respectively. The magnetic induction in $Wb/m^2$ at the centre of the coils will be $(\mu_0 = 4\pi \times 10^{-7} \, Wb/A \cdot m)$.

If $\sin (y+z-x), \sin (z+x-y)$ and $\sin (x+y-z)$ are in $AP$,then

The family of curves in which the sub-tangent at any point to any curve is double the abscissa is given by

Two photons of energy $2.5 \ eV$ and $3.5 \ eV$ fall on a metal surface of work function $1.5 \ eV$. The ratio of the maximum velocities of the photoelectrons emitted from the metal surface is