Hence the intensity of light emerging from P3 will be
I
=I


0
2
2
2
cos
θcos
θ
π –
  = I0 cos2q  sin2q =(I0/4) sin22q
Therefore, the transmitted intensity will be maximum when q = p/4 Rationalised 2023-24
Physics
272
POINTS TO PONDER
1 Waves from a point source spread out in all directions, while light was
seen to travel along  narrow  rays It required the insight and experiment
of Huygens, Young and Fresnel to understand how a wave theory could
explain all aspects of the behaviour of light