In a Young's double-slit experiment the center of a bright fringe occurs wherever waves from the slits differ in phase by a multiple of:
A)"$\pi$/4"
B)"$\pi$/2"
C)"3$\pi$/4"
D)"$\pi$"
E)"2$\pi$"

Question

Quizplus · Accepted Answer

The central bright fringe occurs at the point where the path difference between the waves from the two slits is zero, which corresponds to a phase difference of an integer multiple of $2\pi$. Therefore, the best choice is D, which gives the phase difference as $\lambda/2$ (where $\lambda$ is the wavelength of the light), leading to a path difference of zero at the center.

In a Young's Double-Slit Experiment the Center of a Bright π\piπ

In a Young's Double-Slit Experiment the Center of a Bright $\pi$