A technician wishes to maintain a constant mechanical force of on a straight…
MATHEMATICS · Multi-part · ISC · Mathematics · Physics · Magnetic Effects of Current and Magnetism
Problem
A technician wishes to maintain a constant mechanical force of 1.2N on a straight aluminium rod 0.25m long placed in a uniform magnetic field of 0.30T while the rod is gradually rotated in the field.
(i) Starting from the relevant expression for the magnetic force on a current-carrying conductor, derive an equation giving the current I required to keep the force constant at 1.2N as a function of the angle θ between the rod and the magnetic field.
(ii) Using your derived equation, calculate the current needed when θ=60∘ and when θ=30∘.
(iii) Comment on how the current must be varied as the rod is rotated from a position perpendicular to the field to a position parallel to the field.