Physics Questions + Exams

[taiga]

Well there is a probably a thread for this, but I am too lazy to find it, hence I'll start off with one of mine. (Don't yell at me for being stupid! )

How does inserting an iron core into the coil of a solenoid increase the magnetic field strength?

When referring to a rectangular coil in a motor, why is the length used in F= nBIl only the length parallel to the rotational axis and not the perpendicular length?

P.S I'll attach the source where I am getting the questions from so you guys can give them a shot/see the context they are in. The above aren't actually exam questions, they are just conceptual ones based on other questions.

[Whatlol]

the magnetic forces induced by the current flowing in the perpendicular length doesnt contribute to the torque of the coil, you can prove this to your self by applying the right hand slap rules for different sections of the coils rotation.

I think the iron coil works by magnetic induction, a magnetic field is induced within the core and in turn that magnetic field strengthens the overall magnetic field.