COMEDK20269 May 2026Morning ShiftPhysicsWave OpticsActual
In a Young's double slit experiment, the slits are separated by 0.5 mm. Fringes are obtained on a screen which is placed at distance 1 m away from the slits. When the screen is moved 7 cm farther away, the fringe width changes by 63 m. The wavelength of light used in the experiment will be:
Options
- A4.5 10⁻⁷ m
- B0.5 10⁻⁹ m
- C4.5 10⁻⁶ m
- D0.5 10⁻⁷ m
Correct answer
A. 4.5 10⁻⁷ m
Step-by-step solution
The fringe width in a Young's double slit experiment is given by = D d When the screen is moved by a distance D , the change in fringe width is = D d Rearranging the formula to solve for the wavelength : = d D Substituting the given values = 63 10⁻⁶ m , d = 0.5 10⁻³ m , and D = 7 10⁻² m : = 63 10⁻⁶ 0.5 10⁻³ 7 10⁻² = 31.5 10⁻⁹ 7 10⁻² = 4.5 10⁻⁷ m Answer: 4.5 10⁻⁷ m