A laser shines 630-nm light through a grating producing a first-order (m = 1)maximum at an angle of 30°.A second laser produces a first-order maximum with the same grating at 20°.What is the wavelength emitted by the second laser?
A)945 nm
B)651 nm
C)420 nm
D)431 nm

Question

Quizplus · Accepted Answer

The grating equation is:d(sin θ_m + sin θ_i) = mλwhere d is the grating spacing, θ_m is the angle of the mth-order maximum, θ_i is the angle of incidence, and λ is the wavelength of light.For the first laser, we have:d(sin 30° + sin 0°) = 1(630 nm)d = 315 nmFor the second laser, we have:d(sin 20° + sin 0°) = 1(λ)λ = 431 nm

A Laser Shines 630-Nm Light Through a Grating Producing a First-Order