A straight aluminium rod of length carries a current of while placed in a uniform…
PHYSICS · Subjective · AP · Physics 2: Algebra-based · Magnetism and Electromagnetism · Magnetism and Electromagnetism
Problem
A straight aluminium rod of length 0.25m carries a current of 15A while placed in a uniform magnetic field of strength 0.80T. The rod initially makes an angle of 45∘ with the magnetic field direction.
(i) Derive an expression relating the initial field B1, the initial angle θ1, the final field B2 and the final angle θ2 if the magnitude of the magnetic force on the rod is to remain unchanged when the rod is rotated but the current is kept the same.
(ii) Using the expression obtained, calculate the value of B2 required if the rod is rotated so that it now makes an angle of 30∘ with the field direction.