I know that the torque experience by a current carrying loop in a uniform magnetic field is given by Torque $= MB$ where $M$ is the magnetic moment of the loop. In my book, the derivation was provided only for a rectangular loop and was given that it can be extended to other loops as well.

But intuitively when I try to apply this derivation for a circular coil, I get net torque is equal to $0$. Can somebody help me prove that torque experienced by a current carrying coil in uniform magnetic field is equal to $MB$.

I am currently in high school.

  • $\begingroup$ Would you like to share your work so that we get where you got wrong $\endgroup$
    – Anusha
    Aug 19 '20 at 5:40
  • 1
    $\begingroup$ The torque isn’t simply $MB$. It depends on how the loop is oriented in the field. The torque is the vector product $\vec{M}\times\vec{B}$. $\endgroup$
    – G. Smith
    Aug 19 '20 at 5:47
  • $\begingroup$ -@Niescte, I've answered a question for circular coil. $\endgroup$
    – SarGe
    Aug 19 '20 at 6:15
  • $\begingroup$ What i did was assume that the magnetic field makes and angle theta with the plane of the coil and then observe it from a side so that it looks like a rod.Since the ends have length nearly equal to zero, i got net torque to be equal to 0 exactly like the derivation for a rectangular loop. $\endgroup$
    – Niescte
    Aug 19 '20 at 10:53

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.