An e.m. beam has an intensity of 20 `Ww^(-2)` and is linearly poorised in the vertical direction. Find the intensity of the transmitted beam by a polaroid when its plan of transmission makes an angle of `60^(@)` with the vertical.

A rod of mass m and length l is held vertically on a smooth horizontal floor. Now it is released from this position, find the speed of its centre of mass when it makes an angle theta with the vertical.

A laser beam has intensity 2.5xx10^(14)W/(m^(2)) . Find the amptitude of electric field (in V/m) in the beam.

A uniform rod pivoted at its upper end hangs vertically. It is displaced through anangle of 60^@ and then released. Find the magnitude of the force acting on a particle of mass dm at the tip of the rod when the rod makes an angle of 37^@ with the vertical.

A narrow beam of unpolarised light of intensity I_(0) is incident on a polaroid P_(1) . The light transmitted by it is then incident on a second polaroid P_(2) with its pass axis making an angle of 60^(@) to the pass axis of P_(1) . Find intensity of light transmitted by P_(2) .

A laser beam has intensity 2.5 xx (10^14)W (m^-2). Find the amplitudes of electric and magnetic fields in the beam.

A laser beam has intensity 3.0xx10^14Wm^-2 . Find the amplitudes of electric and magnetic fields in the beam.

A laser beam has intensity 4.0xx10^14Wm^-2 . Find the amplitudes of electric and magnetic fields in the beam.

A simple pendulum is swinging in a vertical plane.The ratio of its potential energies when it is making angles 30^(@) and 60^(@) with the vertical is