Answer:
Highest order: m = 1
Explanation:
Formula for solving this is;
dsin θ_m = mλ
We want to find m, thus;
m = (dsin θ_m)/λ
We are told that White light spans from 380nm - 750 nm. Thus, at maximum, λ = 750 nm.
θ_m = 90°
d = (900 lines/mm) = 9000 × 10^(-7) lines/nm
Since we want to find m, the units nm has to cancel out in the equation.
Thus, we will write d in nm/lines as (10^(7))/9000 nm/lines
Thus;
m = ((10^(7))/9000 × sin 90)/750
m = 1.48
Approximately 1
