Derive an expression for the resultant intensity when two coherent beams of light are superposed for two slits of equal intensity.

As a result of interference of two coherent sources of light, energy is

(a) (i) Two independent mono chromatic sources of light cannot produced a sustained interference pattern'. Give reason. (ii) Light waves each of amplitude ''a'' and frequency ''w'', emanating from two coherent light sources superpose at a point. If the displacements due to these waves is given by y_(3)=a cos omega t and y_(2)=a cos(omega t+phi) where phi is the phase difference between the two, obtain the expression for the resultant intensity at the point. (b) In Young's double slit experiment, using monochromatic light of wavelength lambda , the intensity of light at a point on the screen where path difference is lambda , is K units. Find out the intensity of light at a point where path difference is lambda//3 .

Two incoherent sources of intensities l and 4l superpose then the resultant intensity is

It is found that what waves of same intensity from two coherent sources superpose at a certain point, then the resultant intensity is equal to the intensity of one wave only. This means that the phase difference between the two waves at that point is

When a more intense beam of light is passed during photoelectric effect then :

Waves of same amplitude and same frequency from two coherent source overlap at a point. The ratio of the resultant intensity when they arrive in phase to that when they arrive with 90^(@) phase difference is

Assertion Two coherent sources transmit waves of equal intensity I_(0) Resultant intensity at a point where path difference is lambda/3 is also I_(0) . Reason In interference resultant intensity at any point is the average intensity of two individual intensities.

Young's double-slit experiment setup with ligth of wavelength lambda = 6000 Å , distance between two slit in 2 mm and distance between the plane of slits and the screen. Is 2 m. The slits are of equal intensity. When a sheet of glass of refractive index 1.5 (which permtis only a fraction eta of the incident light to pass through) and thickness 8000 Å is placed in front of the lower slit, it is observed that the intensity at a point P, 0.15 mm above the central maxima, does not change. Intensity at point P is

A : For best contrast between maxima and minima in the interference pattern of Young.s double slit experiment, the intensity of light emerging out of the two slits should be equa. R : The intensity of interference pattern is proportional to square of amplitude.

Two waves having intensity I and 9I produce interference . If the resultant intensity at a point is 7 I , what is the phase difference between the two waves ?