---
title: "Red laser light with wavelength \\(\\lambda_{\\text{red}} = 650\\text{ nm}\\) passes through a single slit of width \\(a\\) and forms a diffraction pattern on a screen located at a distance \\(L\\) from the slit. The red laser is then replaced by a blue laser with wavelength \\(\\lambda_{\\text{blue}} = 450\\text{ nm}\\) passing through the same slit at the same distance. How does the width of the central bright maximum on the screen change, and why?"
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url: "https://nerd-notes.com/ubq/117186/"
date_modified: "2026-08-04T06:44:55+00:00"
---

# Red laser light with wavelength \(\lambda_{\text{red}} = 650\text{ nm}\) passes through a single slit of width \(a\) and forms a diffraction pattern on a screen located at a distance \(L\) from the slit. The red laser is then replaced by a blue laser with wavelength \(\lambda_{\text{blue}} = 450\text{ nm}\) passing through the same slit at the same distance. How does the width of the central bright maximum on the screen change, and why?

Red laser light with wavelength \(\lambda_{\text{red}} = 650\text{ nm}\) passes through a single slit of width \(a\) and forms a diffraction pattern on a screen located at a distance \(L\) from the slit. The red laser is then replaced by a blue laser with wavelength \(\lambda_{\text{blue}} = 450\text{ nm}\) passing through the same slit at the same distance. How does the width of the central bright maximum on the screen change, and why?

![A horizontal schematic viewed from the side. On the left, a laser emits a horizontal beam of light directed to the right toward a vertical barrier containing a narrow single slit of width labeled a. To the right of the barrier at a distance labeled L stands a vertical viewing screen. Light spreads from the slit toward the screen. No other labels, lines, text, or axes appear.](https://nerd-notes.com/wp-content/uploads/ubq-frq-generated/stem-fig-1-1785825895-T79Fla.jpg)

- **A.** The width of the central maximum increases because blue light has a shorter wavelength than red light.
- **B.** The width of the central maximum decreases because blue light has a shorter wavelength than red light.
- **C.** The width of the central maximum decreases because blue light travels slower through the air than red light.
- **D.** The width of the central maximum stays the same because the slit width \(a\) and distance \(L\) remain unchanged.

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/117186/*