A single circular coil of fixed area lies in a uniform magnetic field directed normal…
PHYSICS · Multi-part · AP · Physics 2: Algebra-based · Magnetism and Electromagnetism · Magnetism and Electromagnetism
Problem
A single circular coil of fixed area lies in a uniform magnetic field directed normal to its plane. The magnetic flux linked with the coil varies with time as described below:
• from t = 0 s to t = 2 s it increases uniformly from 0 Wb to 0.25 Wb;
• from t = 2 s to t = 4 s it remains constant at 0.25 Wb;
• from t = 4 s to t = 6 s it decreases uniformly to –0.25 Wb.
(i) For each of the three time intervals (0–2 s), (2–4 s) and (4–6 s), state whether the induced emf in the coil is zero, positive or negative.
(ii) Justify the sign of the induced emf for every interval on the basis of Faraday’s law and Lenz’s law.
(iii) Sketch qualitatively the expected emf–time graph for the complete duration 0 ≤ t ≤ 6 s.