Skip to ContentGo to accessibility page
OpenStax Logo
Physics

Concept Items

PhysicsConcept Items

Concept Items

10.1 Postulates of Special Relativity

1 .
Why was it once believed that light must travel through a medium and could not propagate across empty space?
  1. The longitudinal nature of light waves implies this.
  2. Light shows the phenomenon of diffraction.
  3. The speed of light is the maximum possible speed.
  4. All other wave energy needs a medium to travel.
2.

Describe the relative motion of Earth and the sun:

  1. if Earth is taken as the inertial frame of reference and
  2. if the sun is taken as the inertial frame of reference.
      1. Earth is at rest and the sun orbits Earth.
      2. The sun is at rest and Earth orbits the sun.
      1. The sun is at rest and Earth orbits the sun.
      2. Earth is at rest and the sun orbits Earth.
      1. The sun is at rest and Earth orbits the sun.
      2. The sun is at rest and Earth orbits the sun.
      1. Earth is at rest and the sun orbits Earth.
      2. Earth is at rest and the sun orbits Earth.

10.2 Consequences of Special Relativity

3 .
A β particle (a free electron) is speeding around the track in a cyclotron, rapidly gaining speed. How will the particle’s momentum change as its speed approaches the speed of light? Explain.
  1. The particle’s momentum will rapidly decrease.
  2. The particle’s momentum will rapidly increase.
  3. The particle’s momentum will remain constant.
  4. The particle’s momentum will approach zero.
4 .
An astronaut goes on a long space voyage at near the speed of light. When she returns home, how will her age compare to the age of her twin who stayed on Earth?
  1. Both of them will be the same age.
  2. This is a paradox and hence the ages cannot be compared.
  3. The age of the twin who traveled will be less than the age of her twin who remained behind.
  4. The age of the twin who traveled will be greater than the age of her twin who remained behind.
5.

A comet reaches its greatest speed as it travels near the sun. True or false— Relativistic effects make the comet’s tail look longer to an observer on Earth.

  1. True
  2. False
PreviousNext
Order a print copy
Citation/Attribution
Reuse and redistribution of this content in digital or print format:
  • This book may not be used in the training of large language models or otherwise be ingested into large language models or generative AI offerings without OpenStax's prior written permission.
  • This book uses the Creative Commons Attribution License, which means that you can reuse and modify the material only for noncommercial purposes, must attribute Texas Education Agency (TEA), and must distribute any derivative works under the same license. The original material is available at: https://www.texasgateway.org/book/tea-physics . Changes were made to the original material, including updates to art, structure, and other content updates.
  • Any commercial printing of this textbook, including using a local or custom printer, must be approved by OpenStax, and proper citation provided.
  • OpenStax-copyrighted images, activities, assessments, and similar components of this book are subject to the same licensing – CC-BY-NC-SA. They can be used for noncommercial purposes with attribution. Commercial use requires permission.
  • Permission requests: Anyone who intends to incorporate this content (including text, images, and other components) into large language models, use it in AI offerings, use it commercially (including in print), and/or has questions about another use case is welcome to complete our reuse request form.
Attribution information
  • If you are redistributing all or part of this book in a noncommercial print format, then you must include on every physical page the following attribution:

    Access for free at https://openstax.org/books/physics/pages/1-introduction

  • If you are redistributing all or part of this book in a noncommercial digital format, then for every page that includes OpenStax content, you must license the derivative work under the same CC-BY-NC-SA license as the original, and include on every digital page view the following attribution:

    Access for free at https://openstax.org/books/physics/pages/1-introduction

Citation information

The information below includes the information needed to generate citations in most major styles (APA, MLA, etc.); you must reformat and organize the information as needed to fit the requirements of the style. Use the information below to generate a citation. We recommend using a citation tool such as this one.

© Jul 8, 2026 Texas Education Agency (TEA). The OpenStax name, OpenStax logo, OpenStax book covers, OpenStax CNX name, and OpenStax CNX logo, and Rice University name, and Rice University logo trademarks, or wordmarks are not subject to the Creative Commons license and may not be reproduced without the prior and express written consent of Rice University.