---
title: "An incident photon of wavelength \\(\\lambda_0\\) collides elastically with an electron that is initially at rest. The photon scatters at an angle \\(\\theta\\) relative to its original trajectory with a new wavelength \\(\\lambda’\\), as shown in the diagram. Which of the following graphs best represents the wavelength shift \\(\\Delta \\lambda = \\lambda’ – \\lambda_0\\) as a function of the scattering angle \\(\\theta\\) for angles from \\(0^\\circ\\) to \\(180^\\circ\\)?"
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url: "https://nerd-notes.com/ubq/117484/"
date_modified: "2026-08-04T06:52:20+00:00"
---

# An incident photon of wavelength \(\lambda_0\) collides elastically with an electron that is initially at rest. The photon scatters at an angle \(\theta\) relative to its original trajectory with a new wavelength \(\lambda’\), as shown in the diagram. Which of the following graphs best represents the wavelength shift \(\Delta \lambda = \lambda’ – \lambda_0\) as a function of the scattering angle \(\theta\) for angles from \(0^\circ\) to \(180^\circ\)?

An incident photon of wavelength \(\lambda_0\) collides elastically with an electron that is initially at rest. The photon scatters at an angle \(\theta\) relative to its original trajectory with a new wavelength \(\lambda'\), as shown in the diagram. Which of the following graphs best represents the wavelength shift \(\Delta \lambda = \lambda' - \lambda_0\) as a function of the scattering angle \(\theta\) for angles from \(0^\circ\) to \(180^\circ\)?

![A horizontal dashed line indicates the initial trajectory of an incident photon moving right with wavelength \lambda_0. The photon collides with a stationary electron represented by a shaded circle labeled e^-. After the collision, the scattered photon travels along a path angled upward and to the right at angle \theta relative to the horizontal dashed extension line, with wavelength \lambda'. The recoiling electron moves downward and to the right at angle \phi below the horizontal line. An arc labeled \theta measures the angle between the horizontal extension line and the scattered photon path. No other labels, lines, or text appear.](https://nerd-notes.com/wp-content/uploads/ubq-frq-generated/stem-fig-1-1785826338-ra1bcl.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/117484/*