If the wavelength of light in Young's two-slit experiment is decreased, which one of the following statements is true of the interference pattern?
A) The distance between the minima stays the same.
B) The distance between the maxima decreases.
C) The distance between maxima stays the same.
D) The distance between the maxima increases.
E) Impossible to tell without knowing the separation between the slits.

Question

Quizplus · Accepted Answer

According to the equation for the position of maxima and minima in Young's double-slit experiment, d sin(theta) = m(lambda), where d is the distance between the slits, theta is the angle between the central maximum and the mth maximum, lambda is the wavelength of the light, and m is an integer. As lambda decreases, for a fixed distance between the slits, sin(theta) decreases, which means that theta decreases. Since the distance between maxima is proportional to the sine of the angle between them, decreasing theta leads to a decrease in the distance between the maxima. Therefore, the correct answer is B - the distance between the maxima decreases.

If the Wavelength of Light in Young's Two-Slit Experiment Is