A pair of narrow parallel slits separated by a

Question

distance of 0.253 mm are illuminated by the
green component from a mercury vapor lamp
(λ = 545.1 nm).
What is the angle from the central maximum to the first bright fringe on either side of
the central maximum?
Answer in units of
◦

Answer 1

tanα = x(max1)/L = λ/d =545.1•10^-9/0.253•10^-3 =2.15•10^-3
α = 0.123 o

Answer 2

Im sorry to ask again but what equation did you use? Can you list the steps you did please?

So I can answer the next few questions by myself.