A straight metallic rod of length is moved with a uniform velocity through a region…
PHYSICS · Subjective · A Level · Physics · Fields and their consequences · Fields and their consequences
Problem
A straight metallic rod of length L is moved with a uniform velocity v through a region of uniform magnetic field B that is perpendicular to the plane of motion.
(i) State Faraday’s law of electromagnetic induction.
(ii) Explain, with reference to the force experienced by free electrons, why an electromotive force (emf) is developed between the ends of the rod when it moves perpendicular to B.
(iii) Write the expression obtained for the magnitude of this emf and clearly identify each physical quantity on which it depends.
(iv) Why does the emf become zero if the rod moves parallel to the magnetic field?
(v) If the rod forms one side of a closed rectangular circuit lying in the field, describe the direction of the induced current and justify your answer using Lenz’s law.