The ratio of intensity at the centre of a bright fringe to the intensity at a point distance one-fourth of the distance between two successive bright fringes will be

Step-by-step solution

Intensity at centre of bright fringe, I 0 = I + I + 2 I I · cos 0 I 0 = 2 I + 2 I ∵   cos 0 ° = 1 = 4 I Similarly Intensity at point P 4 (with phase difference = 2 π 4 = π 2 ) I ' = I + I + 2 I I cos π 2 = 2 I + 2 I I × 0 = 2 I ∴   I 0 I ' = 4 I 2 I = 2