---
title: "A monochromatic laser beam of wavelength \\(\\lambda\\) is incident normally on a barrier containing two narrow slits separated by a center-to-center distance \\(d\\). The resulting light intensity pattern observed on a distant screen is shown in the graph, where \\(y\\) is the position along the screen and \\(y_1\\) is the location of the first-order principal maximum. The two-slit barrier is then replaced with a four-slit barrier having the exact same slit width and center-to-center slit spacing \\(d\\). Which of the following graphs best represents the new light intensity \\(I\\) on the screen as a function of position \\(y\\)?"
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url: "https://nerd-notes.com/ubq/123426/"
date_modified: "2026-09-28T11:58:31+00:00"
---

# A monochromatic laser beam of wavelength \(\lambda\) is incident normally on a barrier containing two narrow slits separated by a center-to-center distance \(d\). The resulting light intensity pattern observed on a distant screen is shown in the graph, where \(y\) is the position along the screen and \(y_1\) is the location of the first-order principal maximum. The two-slit barrier is then replaced with a four-slit barrier having the exact same slit width and center-to-center slit spacing \(d\). Which of the following graphs best represents the new light intensity \(I\) on the screen as a function of position \(y\)?

A monochromatic laser beam of wavelength \(\lambda\) is incident normally on a barrier containing two narrow slits separated by a center-to-center distance \(d\). The resulting light intensity pattern observed on a distant screen is shown in the graph, where \(y\) is the position along the screen and \(y_1\) is the location of the first-order principal maximum. The two-slit barrier is then replaced with a four-slit barrier having the exact same slit width and center-to-center slit spacing \(d\). Which of the following graphs best represents the new light intensity \(I\) on the screen as a function of position \(y\)?

![A 2D Cartesian plot showing relative intensity on the vertical axis versus position y on the horizontal axis. The vertical axis is labeled I and has no grid lines. The horizontal axis is labeled y and features five tick marks symmetrically arranged about the origin: -2y_1, -y_1, 0, y_1, and 2y_1. A solid curve depicts a smooth, periodic interference pattern with broad peaks of equal maximum height located precisely at y = -2y_1, -y_1, 0, y_1, and 2y_1. The curve reaches zero intensity at the midpoints between adjacent peaks, specifically at y = -1.5y_1, -0.5y_1, 0.5y_1, and 1.5y_1. There are no secondary peaks between the main peaks. No other labels, lines, text, or axes appear.](https://nerd-notes.com/wp-content/uploads/ubq-frq-generated/stem-fig-1-1790596710-XmJRb4.jpg)

- **A.** Graph A
- **B.** Graph B
- **C.** Graph C
- **D.** Graph D

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/123426/*