NTA Abhyas JEE Main2020PhysicsWave OpticsPractice
Two point white dots are 1 mm apart on a black paper. They are viewed by an eye of pupil diameter 3 mm . Approximately, what is the maximum distance at which these dots can be resolved by the eye? [Take wavelength of light = 500 nm ]
Options
- A6   m
- B3   m
- C1   m
- D5   m
Correct answer
D. 5   m
Step-by-step solution
Resolution limit = 1.22 λ d Again resolution limit = sin θ = θ = y D ∴ y D = 1 · 22 λ d D = y d 1.22 λ D = 10 - 3 × 3 × 10 - 3 1.22 × 5 × 10 - 7 = 30 6.1 ≈ 5  m .