450 nm of light falls on a single slit of width 0.30 mm. What is the angular width of the central diffraction peak?
A) 0.086°
B) 0.13°
C) 0.17°
D) 0.26°
E) 0.35°

Question

Quizplus · Accepted Answer

The angular width of the central diffraction peak can be approximated by:
θ ≈ λ/w
where λ is the wavelength and w is the width of the slit.

Substituting the given values, we get:
θ ≈ (450 nm)/(0.30 mm) = 0.15°

However, this is the angular width of both sides of the central maximum, so the angular width of the central maximum itself would be half of this, or:
θ = 0.15°/2 = 0.075°

Rounding this to two significant figures gives:
θ ≈ 0.17°, which is closest to answer choice C.

450 Nm of Light Falls on a Single Slit of Width