Speaking of coils and torque here, So I have a coil and after I did fleming's right hand rule to get the direction of the torque (let it be the positive x-axis unit vector î can't remember it correctly) I was asked to get it's direction of rotation: whether it is clockwise or anti-clockwise. What I tried is handling segments of the coil separately to know the direction of rotation but that didn't help me much as the coil was on xy plane, I kept imagining it but I can't figure out if its clockwise or anti I mean it depends whether I look at it from the right or the left, I also tried right hand screw rule but It made no sense to me, at last I tried to look it up on Internet but didn't really find any results so I head over here in hope I get help. Thank you Edit(2): I am not allowed to post pictures, and not familiar with mathjax I use the app on my phone I will try to describe one of the two problems I am talking about: Rectangular coil of 20 turns and an area of 0.005 square meters, carrying current of 10A, Its hinged along the y-axis and mounted on XY plane at an angle of 30 degrees to a uniform magnetic field of 0.5 tesla, Find the torque vector and the direction of rotation of the coil. So the coil has one long side on y and one short side on x (axis) the direction of current is also given So tau=NI AxB is what I did after resolution of B into a vector and what I got was 4.33*10^-3 (-y axis unit vector) But I am struggling with the direction of rotation for the coil

  • $\begingroup$ Pardon me, stack exchange didn't allow me to post photos due reputation I will update with some detailed context. $\endgroup$ – user597368 Jan 5 '19 at 17:52
  • $\begingroup$ Also, please format your question properly and use Mathjax to write math expressions. $\endgroup$ – Harshit Joshi Jan 5 '19 at 18:09

Are you familiar with the Magnetic Moment Vector?

As a thumb rule you can remember that it wants to align itself to the Magnetic Field.

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  • $\begingroup$ Yes I do, it's the same as the direction of the torque vector , what exactly is trying to align it self? The coil plane? $\endgroup$ – user597368 Jan 5 '19 at 18:05
  • $\begingroup$ This vector aligns to the magnetic field($\vec B$). You can determine Clockwise or Anticlockwise that way. $\endgroup$ – Harshit Joshi Jan 5 '19 at 18:06
  • $\begingroup$ In my case the magnetic field vector has 2 component one with x and another with z so I will align with the one which is parallel to the plane which is with x and it will seem to rotate clockwise, alright thanks $\endgroup$ – user597368 Jan 5 '19 at 18:14
  • $\begingroup$ @user597368 Please accept this answer if it solved your queries. $\endgroup$ – Harshit Joshi Jan 5 '19 at 18:16

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