Why does a solenoid with current rotate in a magnetic field?

[Evenus1]

hi
i was wonder as to why when an solonid is placed with a current within and magnet there's a an rotational force. why is it that he difrence in strength of magnetic field created results in an rotation
many thanks
Ewen

 

[BvU]

Have you heard of the Lorentz force ? Nice show here, explained https://www.boundless.com/physics/textbooks/boundless-physics-textbook/magnetism-21/magnetic-fields-magnetic-forces-and-conductors-159/torque-on-a-current-loop-rectangular-and-general-561-6351/