Which of the following equations describes the condition for observing the fourth bright fringe in Young's double-slit interference pattern? Assume n = 0 for the central bright fringe.

Question

d sinθ = λ

d sinθ = 3λ/2

d sinθ = 3λ

d sinθ = 4λ

Answer 1

d•sinθ=2k•λ/2=k λ
k=4
d sinθ = 4λ