NTA Abhyas JEE Main2020PhysicsWave OpticsPractice
In Young's double-slit experiment interference bands are produced on the screen placed at 1.5 m from two slits 0.15 mm apart and illuminated by the light of wavelength 6000 Å . If the screen is now taken away from the slits by 50 cm then find the change in fringe width (in mm)?
Correct answer
2
Step-by-step solution
D 2 - D 1 = 50 c m ; D 1 = 1.5 m = 150 c m λ = 6000 Å = 6000 × 10 - 8 c m ; d = 0.15 m m Change in fringe width ∆ β = β 2 - β 1 ∆ β = D 2 - D 1 λ d = 50 × 6000 × 10 - 8 0.15 × 10 - 1 ∆ β = 20 × 10 - 4 10 - 3 = 2 × 10 - 1 c m = 2 m m ∆ β = 2 m m