A square coil of side and turns has a total resistance of
PHYSICS · Multi-part · A Level · Physics · Fields and their consequences · Fields and their consequences
Problem
A square coil of side 20cm and 50 turns has a total resistance of 2.0Ω. It is placed with its plane perpendicular to a uniform magnetic field that varies with time as follows:
• From t=0 to t=0.10s, the field increases uniformly from 0.10T to 0.60T.
• From t=0.10s to t=0.30s, the field decreases uniformly back to 0.20T.
(i) Sketch qualitatively the variation of magnetic field with time over the given interval, clearly marking numerical values on both axes.
(ii) Determine the magnitude and direction of the induced emf during the first interval (0≤t≤0.10s).
(iii) Obtain an expression for the induced emf during the second interval and calculate its value at t=0.20s.
(iv) Compute the total heat produced in the coil during the entire 0.30s period.