What resolving power must a diffraction grating have in order to distinguish wavelengths of 635.40 nm and 636.60 nm? (1 nm = 10^-9m) A)318 B)530 C)636 D)848

Question

Quizplus · Accepted Answer

The resolving power of a diffraction grating is given by the equation: 
R = Nm, where R is the resolving power, N is the number of lines in the grating, and m is the order of the diffraction maximum. 
For the given wavelengths, we have: 
R = Nm = (636.60-635.40)/635.40 = 0.00189 
Therefore, Nm = 1/0.00189 = 529.10 
Rounding up to the nearest integer gives the answer of 530. Therefore, the best choice is B.

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