JEE Main202118 Mar 2021Morning ShiftPhysicsWave OpticsActual
In Young's double slit arrangement, slits are separated by a gap of 0 . 5 mm , and the screen is placed at a distance of 0 . 5 m from them. The distance between the first and the third bright fringe formed when the slits are illuminated by a monochromatic light of 5890 A o is :-
Options
- A1178   ×   10 – 9   m
- B1178   ×   10 – 6   m
- C1178   ×   10 – 12   m
- D5890   ×   10 – 7   m
Correct answer
B. 1178   ×   10 – 6   m
Step-by-step solution
β = λ D d = 5890 × 10 - 10 × 0 . 5 0 . 5 × 10 - 3 = 589 × 10 - 6   m Distance between first and third bright fringe is 2 β = 2 × 589 × 10 - 6   m = 1178 × 10 - 6   m