Single-slit diffraction: A single slit forms a diffraction pattern, with the first minimum at an angle of 40.0° from central maximum, when monochromatic light of 630-nm wavelength is used. The same slit, illuminated by a new monochromatic light source, produces a diffraction pattern with the second minimum at a 60.0° angle from the central maximum. What is the wavelength of this new light?
A) 425 nm
B) 450 nm
C) 475 nm
D) 500 nm
E) 525 nm

Question

Quizplus · Accepted Answer

The angle for the m-th minimum in single-slit diffraction is given by $ a \sin \theta = m \lambda $. For the first light source, $ a \sin 40^\circ = 1 \times 630 \, \text{nm} $. For the second light source, $ a \sin 60^\circ = 2 \times \lambda $. Solving these equations gives $ \lambda = 425 \, \text{nm} $.

Single-Slit Diffraction: a Single Slit Forms a Diffraction Pattern, with the First