(a) Derive an expression for the current I required to support, in a horizontal position, a straight conductor of mass per unit length λ placed at right angles to a uniform magnetic field of flux density B.
(b) A wire 0.60 m long has a mass of 15 g. It is placed horizontally in a magnetic field of 0.30 T at right angles to the field direction. Calculate the current needed to keep the wire in equilibrium.
(c) If the strength of the magnetic field is doubled while the mass of the wire remains the same, what happens to the current required for equilibrium? Give numerical value and comment on the relationship observed.