NTA Abhyas JEE Main2020PhysicsWave OpticsPractice
Fraunhofer diffraction pattern of a single slit is obtained in the focal plane of the lens of focal length 1 m . If the third minimum is formed at a distance of 5 mm from the central maximum and wavelength of light used is 5000 A ∘ , then the width of the slit will be
Options
- A0 . 02   cm
- B0 . 03 cm
- C0 . 04 cm
- D1 cm
Correct answer
B. 0 . 03 cm
Step-by-step solution
Using a sin θ = n λ Or a . x f = 3 λ or a = 3 λ . f x = 3 × 500 × 10 - 9 × 1 5 × 10 - 3 = 3 × 10 - 4 m = 0.03 c m