A diffraction pattern is produced on a viewing screen by illuminating a long narrow slit with light of wavelength $\lambda$.If $\lambda$ is increased and no other changes are made:
A)the intensity at the center of the pattern decreases and the pattern expands away from the bright center
B)the intensity at the center of the pattern increases and the pattern contracts toward the bright center
C)the intensity at the center of the pattern does not change and the pattern expands away from the bright center
D)the intensity at the center of the pattern does not change and the pattern contracts toward the bright center
E)neither the intensity at the center of the pattern nor the pattern itself change

Question

Quizplus · Accepted Answer

Increasing the wavelength $\lambda$ causes the diffraction pattern to expand, as the angular width of the central maximum is proportional to $\lambda$. The intensity at the center does not change because it depends on the slit width and the light's amplitude, not the wavelength.

A Diffraction Pattern Is Produced on a Viewing Screen by Illuminating