Question
Use Faraday’s law, Lenz’s law, and RHR-1 to show that the magnetic force on the current in the moving rod in Figure 23.11 is in the opposite direction of its velocity.
<b>Figure 23.11</b> A motional EMF is induced between the rails when this rod moves to the right in the uniform magnetic field. (b) Lenz’s law gives the directions of the induced field and current, and the polarity of the induced emf.
Figure 23.11 A motional EMF is induced between the rails when this rod moves to the right in the uniform magnetic field. (b) Lenz’s law gives the directions of the induced field and current, and the polarity of the induced emf.
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Final Answer

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Solution video

OpenStax College Physics for AP® Courses, Chapter 23, Problem 15 (Problems & Exercises)

OpenStax College Physics, Chapter 23, Problem 15 (PE) video thumbnail

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Video Transcript
This is College Physics Answers with Shaun Dychko. As this rod moves to the right, there's an increasing area enclosed by this loop which is causing an increased flux and that's going to induce a current that decreases this flux. And so, the current is going to be going in the direction shown here with this blue arrow. And, now we use the right hand rule to figure out what direction of the force applied by this magnetic field will be on this current-carrying wire. So, we put our thumb in the direction of current to the wire which is upwards and our fingers should go in the direction of magnetic field, which is into the page, and then the palm is pushing in the direction the force would be, and that force would be to the left. And, there we go.