In an AC circuit $E = 50 \sin(500 t)$, $I = 600 \sin\left(500 t + \dfrac{\pi}{3}\right) mA$. What is the power dissipated in the circuit? [$\cos 60^\circ = 0.5$]

In the circuit shown below, the ac source has voltage $V = 30 \cos(\omega t)$ volt with $\omega = 2000$ rad/s. What will be the amplitude of the current?

For large magnifying power of a telescope

A ray of light is incident of the surface of a glass plate at an angle of incidence equal to Brewster's angle $\Phi$. If $\mu$ denotes the refractive index of glass w.r.t. air, then what will be the angle between reflected and refracted rays?