A beam of plane polarised light falls normally on a polariser (cross-sectional area `3 xx 10^(-4) m^2`),which rotates about the axis of the ray with an angular velcity of `31.4 rads^(-1)`.Find the energy of light passing through the polariser per revolution and the intensity of emergent beam,if flux of energy of the incident ray is `10^-3)W`.

A particle has an angular speed of 3 rad/s and the axis of rotation passes through the points (1,1,2)a n d(1,2,-2)dot Find the velocity of the particle at point P(3,6,4)dot

A current of 5A is passing through a metallic wire of area of cross-section 4xx10^-6m^2 , If the density of charge carriers of the wire is 5xx10^26m^−3 find the drift velocity of electrons.

A light beam, emanating from the point A (3, 10) reflects from the straight line 2x+y-6=0 and then passes through the point B(4, 3) . Find the equations of the reflected beams.

Consider a light beam incident from air to a glass slab at Brewster's angle as shown in Fig. EP 10.1. A polarised is placed in the path of the emergent ray at point P and rotated about an axis passing through the center and perpendicular to the plane of the polaroid.

Light from an ordianry source(say a sodium lamp) is passed through a polaroid sheet P_1 .The transmitted light is then made to pass through a second polaroid sheet P_2 ,which can be rotated so that the angle (theta) betwen the two polaroid sheets varies from 0^@ to 90^@ .Show graphically the variation of he intensity of light transmitted by P_1 and P_2 as a function of the angle theta .Take the incident beam intensity as I_0 . Why does the light from a cleear blue portion of the sky,show a rise and fall on intesnity,when viewed through a polaroid ,which is rotated?

A current of 1.8 A flows through a wire of cross-sectional area 0.5 mm^(2) ? Find the current density in the wire. If the number density of conduction electrons in the wire is 8.8 xx 10^(28) m^(-3) , find the drift speed of electrons.

Unpolarised light of intensity 32 W m^(-2) passes trough three polarisers,such that transmission axis of last polariser is crossed with the first.If intensity of ermerging light is 3W m^(_2) ,what is the angle between the transmission axis of the first two,polarisers?At what angle will the inensity of transmitted light be maximum?

Find the co-ordinates of the point P, where the line through A(3,-4,-5) and B(2,-3,1) crosses the plane passing through three points L(2,2,1), M(3,0,1) and N(4,-1,0). Also, find the ratio in which P divides the line segment AB.

Three polaroids are placed insuch a manner that the third polaroid is crossed with the first.When a beam of unpolarised light of intenstiy 24 W m^(-2) falls on the first polaroid,the intensity of light reduces to 3W m^(-2) on emerging fromo the thrid polariod.Find the angle between the trnasmission axes of the second and third polaroid.