Given below are two statements:
Statement I: In a Young's double slit experiment, the angular separation of fringes will increase as the screen is moved away from the plane of the slits
Statement II : In a Young's double slit experiment, the angular separation of fringes will increase when monochromatic source is replaced by another monochromatic source of higher wavelength
In the light of the above statements, choose the correct answer from the options given below:
Statement I: In a Young's double slit experiment, the angular separation of fringes will increase as the screen is moved away from the plane of the slits
Statement II : In a Young's double slit experiment, the angular separation of fringes will increase when monochromatic source is replaced by another monochromatic source of higher wavelength
In the light of the above statements, choose the correct answer from the options given below:
- (A)Both Statement I and Statement II are true
- (B)Both Statement I and Statement II are false
- (C)Statement I is false but Statement II is true✓ Correct
- (D)Statement I is true but Statement II is false
Answer: (C)
Solution
The angular fringe width in a double-slit pattern is , fixed only by the wavelength and the slit separation and independent of the screen distance; moving the screen farther away leaves it unchanged, so Statement I is false. Because grows with , replacing the source by one of higher wavelength widens the angular separation, so Statement II is true. Statement I is false but Statement II is true.
JEE Main · 2026 · 21 Jan 2026 · Shift 2 · Single correct option