What is the angular separation of the two second-order spectral lines having wavelengths 417 nm and 388 nm using a diffraction grating having 456 lines/mm?
A) 1.63°
B) 1.52°
C) 0.815°
D) 3.26°

Question

Quizplus · Accepted Answer

Using the formula for the angular separation of spectral lines from a diffraction grating:
Δθ = d/λ
where d is the grating spacing (1/density) and λ is the wavelength of light
We can calculate the grating spacing:
d = 1/456 lines/mm = 2.192 x 10^-3 mm/line
Then we can plug in the values for each of the two spectral lines and calculate the angular separation:
Δθ = (2.192 x 10^-3 mm/line) x ((1/417 nm) - (1/388 nm))
Δθ = 1.63°
Therefore, the answer is  A) 1.63°.

What Is the Angular Separation of the Two Second-Order Spectral