A straight aluminium wire of length 0.40 m carries a current of 8.0 A inside a…
PHYSICS · Multi-part · A Level · Physics · Fields and their consequences · Fields and their consequences
Problem
A straight aluminium wire of length 0.40 m carries a current of 8.0 A inside a uniform magnetic field of 0.25 T. The wire is initially oriented at 60° to the field.
(a) Write the general expression for the magnitude of the magnetic force on the wire, identifying each physical quantity involved.
(b) Calculate the magnitude of the force in the initial orientation.
(c) The current is reduced to 4.0 A and simultaneously the magnetic field strength is increased to 0.75 T. Determine the angle the wire must now make with the magnetic field so that the magnitude of the force remains the same as in part (b).
(d) Comment on whether more than one orientation satisfies the condition obtained in part (c), and justify your answer mathematically as well as physically.