Select the correct option for the statements given below.
(A) The diffraction pattern is a superposition of waves originating from each point on a single slit.
(B) The interference pattern is the superposition of two waves originating from two narrow slits.
(C) The diffraction pattern in single slit has a central bright maximum brighter than other maxima.
(D) The interference in double slit has a number of equally spaced bright and dark bands.
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → (A), (B), (C) and (D) are correct
Each statement is checked against the standard description of diffraction by a single slit and interference by a double slit.
(A) The diffraction pattern is a superposition of waves originating from each point on a single slit — Correct. By Huygens’ principle every point of the slit acts as a source, and the pattern is the superposition of these secondary waves.
(B) The interference pattern is the superposition of two waves originating from two narrow slits — Correct. Two coherent beams from the two slits overlap on the screen.
(C) The diffraction pattern in single slit has a central bright maximum brighter than other maxima — Correct. The central maximum is the brightest and twice as wide as the secondary maxima, whose intensity falls off rapidly.
(D) The interference in double slit has a number of equally spaced bright and dark bands — Correct. The fringe width \( \beta = \frac{\lambda D}{d} \) is the same for all fringes.
NCERT (2026-27):
The Single Slit – “… The basic idea is to divide the slit into much smaller parts, and add their contributions at P with the proper phase differences. We are treating different parts of the wavefront at the slit as secondary sources.”
Summary – “… 4. Young’s double slit of separation d gives equally spaced interference fringes. 5. A single slit of width a gives a diffraction pattern with a central maximum.”