# Newton's 3rd law coil in magnetic field

When a current-carrying rectangular loop is placed in a magnetic field, the forces acting on either side of the loop which is perpendicular to the field provides a torque which rotates the loop.

However, according to Newton's 3rd Law, there should be some equal and opposite force acting on the object exerting the force. But in fields, it is the field that exerts forces on objects. Does that mean that the loop exerts an equal and opposite force on the magnet or on the magnet's field? How do these forces play out and what effect do they have on the magnet?

• Interesting! As far as I know, Newton's laws were never meant for force-fields - they define force itself and acceleration as its consequence. Hail Oersted, for he unleashed the tormenting truth of fields (magnetic fields, though it was later generalized to all kinds of forces). Commented Feb 20, 2021 at 5:51
• I would rather suggest to read Faraday's or Maxwell's on the idea of lines of force. Commented Feb 20, 2021 at 5:53
• This is a great answer physics.stackexchange.com/questions/114466/… Commented Feb 20, 2021 at 6:07
• this wikipedia is pretty good as well en.wikipedia.org/wiki/Momentum#Electromagnetic Commented Feb 20, 2021 at 6:21
• Fleming's right hand rule described that flow of electrical current in the loop (flipping the bird sign) will induce a magnetic field acting on the magnetic field from the permanent magnet (reprimanding sign) which then result in a magnetic force (compliment sign) so it is 2 magnetic fields battle royale ;D Commented Feb 20, 2021 at 6:34