What is the minimum number of slits required in a diffraction grating to just resolve light with wavelengths of 471.0 nm and 471.6 nm?
A)99
B)197
C)393
D)786
E)1179

Question

Quizplus · Accepted Answer

The resolving power R of a diffraction grating is given by R = λ/Δλ = mN, where m is the order of diffraction, N is the number of slits, λ is the average wavelength, and Δλ is the difference in wavelengths. For the first order (m=1), N = λ/Δλ = 471.3/0.6 ≈ 393.

What Is the Minimum Number of Slits Required in a Diffraction