A diffraction grating has 300 lines per mm.If light of wavelength 630 nm is sent through this grating,what is the highest order maximum that will appear?
A) 8
B) 2
C) 6
D) 5
E) 5.3

Question

Quizplus · Accepted Answer

The formula for finding the highest order maximum is given as:

n(max) = d / λ
where:
d = distance between adjacent slits (which is equal to 1/300 mm for this grating)
λ = wavelength of light (which is given as 630 nm)

Thus, n(max) = (1/300 mm) / (630 nm) = 5.03

Since n(max) must be a whole number, the highest order maximum that will appear is 5.

A Diffraction Grating Has 300 Lines Per Mm