A single–turn rectangular coil of sides and is placed in a uniform magnetic field…
PHYSICS · Multi-part · A Level · Physics · Fields and their consequences · Fields and their consequences
Problem
A single–turn rectangular coil of sides l and w is placed in a uniform magnetic field B that makes an angle θ with the normal to the plane of the coil.
Answer the following questions in the order given.
(i) Define magnetic flux linked with the coil and write its expression in terms of B, A and θ.
(ii) State Faraday’s law of electromagnetic induction and explain the significance of the negative sign that appears in its mathematical form.
(iii) Keeping the values of B and A constant, describe qualitatively how an emf can be induced in the coil by changing only the orientation of the coil. Give a physical reason for the direction of the induced current.
(iv) For a small angular displacement dθ of the coil about an axis in its plane during a short time interval dt, show that the magnitude of the induced emf is proportional to sinθ(dθ/dt). State all assumptions clearly.