Electricity and Magnetism: Forces on Conductors in Magnetic Fields

[spaghetti3451]

Homework Statement

(i) What is the strength and direction of the force per unit length acting on a straight conductor carrying an electrical current, I, in a magnetic field, B?

(ii) The figure below shows a square frame of aluminium set at an angle θ to the direction of a strong static magnetic field, B, parallel to the x-axis (the y-axis is vertical). The frame has sides of length L and the arms have cross-sectional area A, with L >> √A. Write down expressions for the electrical resistance (for currents flowing around the frame) and the total mass if the density and conductivity of aluminium are ρ and σ respectively.

(iii) left out for the moment

Homework Equations

The Attempt at a Solution

(i) F = B x Il,
so F/l = BIsinφ, where φ is the angle between the direction of force and the length of the conductor and the force acts in a direction which is perpendicular to the magnetic field and the length of the conductor.

(ii) Electrical resistance R = L/σA

Total mass = ρV = ?

Any comments would be greatly appreciated.

 

[Quinzio]

Well, V=LA.

 

[spaghetti3451]

Well, I know that but the problem is part of the frame is missing, so don't know how to take that into account.