Question
re-La b #ll:Diffraction Name: Section: M T WR 2P 5P 1. Light from a red laser passes through a sing increased by a factor of two, what e: Assume that the angle is suffi a sit to form a diffraction pattern. If the width of the slit the central maximum? ientlysniall solat (sine, is nearly eq (a) The width of the central maximum increases by a factor of 4 (b) The width of the central maximum decreases by a factor of 4 (c) The width of the central maximum decreases by a factor of 4 (d) The width of the central maximum increases by a factor of 2 (e) The width of the central maximum does not change. 2. The table lists the range of wavelengths in vacuum corresponding to a given color. Which one of these colors will produce a diffraction pattern with the widest central maximum, assuming all other factors are equal? 780 622 622 597 597-577 577-492 492 -455 455 -390 orange yellow blue violet (d) blue (e) violet (a) red (b) yellow (c) green
Explanation / Answer
1)
Ans: (b) The width of the central maximum decreases by a factor of 2.
When we increase the width of the slit, the central maximum in the diffraction pattern gets narrower. This is true for single slits, double slits, and diffraction gratings. The smaller the object the wave interacts with, the more spread there is in the interference pattern. Increasing the size of the opening reduces the spread in the pattern.
