Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. It's 100% free.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

enter image description here

Could someone explain what the green underlined part means? It doesn't make sense to me. It says the current (induced) flows CCW (that means towards the right). Then it says it flows to the left?

share|cite|improve this question
up vote 1 down vote accepted

I guess the circuit is closed somewhere at the bottom of the frame, so the current flows up the right part of the frame, to the left in the wire, and down in the right part of the frame - so it's CCW, indeed.

share|cite|improve this answer
sorry I did not understand that at all. I have no idea what you just said. – Hawk Aug 6 '12 at 1:09
@jak: Let me try to explain. DC current does not flow in a circuit, unless the circuit is closed (if you do not know what a "closed circuit" means, try to find this out somewhere else, I don't have time to explain this). Therefore, I assume that the left and the right parts of the frame are connected not only by the wire in your picture, but also by another conductor (probably, somewhere lower than the wire). So the closed circuit is formed by the wire, the left and right parts of the frame and by this additional conductor, and the current flows CCW in this circuit. – akhmeteli Aug 6 '12 at 1:18
@akhmetli I think found my answer in my book. Basically it's flowing to the left because the area enclosed gets smaller and by Lenz's Law the current starts to flow the other way (CW) to oppose the change. Also the picture got cut off. There is supposed to be a resistor at the bottom that connects the two vertical bars – Hawk Aug 6 '12 at 1:29
@jak: And I did tell you there should be a conductor at the bottom. However, if the current flows to the left in the wire, the current flows CCW in the circuit, not CW. – akhmeteli Aug 6 '12 at 5:01

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.