Single-slit diffraction: If the fifth order minimum in the diffraction pattern of a thin slit is at 40° from the central maximum, what is the highest order minimum in the pattern?
A) 6
B) 11
C) 8
D) 7
E) 9

Question

Quizplus · Accepted Answer

The condition for minima in single-slit diffraction is given by $ a \sin \theta = m \lambda $, where $ a $ is the slit width, $ \theta $ is the angle, $ m $ is the order of the minimum, and $ \lambda $ is the wavelength. The maximum possible value for $ \sin \theta $ is 1, so the highest order $ m $ is when $ m \lambda = a $. Given that the fifth order minimum is at 40°, we can calculate the highest order by considering the limit $ \sin \theta = 1 $. Solving for $ m $ gives the highest order as 7.

Single-Slit Diffraction: If the Fifth Order Minimum in the Diffraction