Question

A single slit of width b is illuminated by a coherent monochromatic light of wavelength . If the second and fourth minima in the diffraction pattern at a distance 1 m from the slit are at 3 cm and 6 cm respectively from the central maximum, what is the width of the central maximum ? (i.E. Distance between first minimum on either side of the central maximum)

Answer 1

Hey dear,

● Answer- 3 cm.

● Explanation-
Distance of 2nd maxima from the slit-
x2 = 2λ/D

Distance of 4th maxima from the slit-
x4 = 4λ/D

Difference between
x4 - x2 = 4λ/D - 2λ/D
x4 - x2 = 2λ/D

Central maxima width is-
W = 2λ/D
W = (x4 - x2) D
W = (6 - 3) 1
W = 3 cm.

Width of central maxima is 3 cm.

Hope this is helpful...