Two identical sources of spherical electromagnetic waves emit in phase at the powerP1 = P2= 20 W. The waves have a wavelength ? = 500 nm and are linearly polarizedalong the direction joining the two sources. The distance between the two sources is d = 1 cm. Adistance L = 10 m and placed a screen on which the interference pattern is observed. `

a) Determine the number of maxima observed between the points O and P, distant ?x = 6 cm.

Subsequently, a thick polaroid plate is placed in front of one of the two sourcess = 1 m, relative dielectric constant er= 3 and relative magnetic permeability r=1, with the axisof polarization forming an angle ? = 45?with the electric field of the wave.

b) Determine the value of the luminous intensity in O.