NTA Abhyas JEE Main2020PhysicsWave OpticsPractice
Consider the interference at P between waves emanating from three coherent sources in the same phase located at S 1 , S 2 and S 3 . If the intensity due to each source is I 0 = 12 W m - 2 at P and d 2 2 D = λ 3 then what will be the resultant intensity (in W m - 2 ) at P ?
Correct answer
36
Step-by-step solution
S 2 P – S 1 P = d sin θ 1 = d . d / 2 D = d 2 2 D = λ 3 S 3 P – S 2 P = d sin θ 2 = d 3 d / 2 D = 3 d 2 2 D = λ I Resultant = I 0 + 4 I 0 + 2 I 0 4 I 0 c o s 120 0 = 3 I 0