A coil of turns and rectangular shape is rotated about one of its longer edges with a…
PHYSICS · Multi-part · A Level · Physics · Fields and their consequences · Fields and their consequences
Problem
A coil of N turns and rectangular shape (lengthl,breadthb) is rotated about one of its longer edges with a constant angular speed ω in a uniform magnetic field of magnitude B. At t=0 the plane of the coil is perpendicular to the magnetic field.
(a) Write an expression for the magnetic flux linked with the coil at an arbitrary time t.
(b) Hence obtain an expression for the instantaneous induced emf in the coil as a function of time.
(c) Show that the maximum value of the emf is NBlbω.
(d) If N=200, l=20cm, b=12cm, B=0.30T and ω=50rads−1, calculate:
(i) the peak emf,
(ii) the rms value of the emf.
(e) Sketch one complete variation of the induced emf with time, clearly marking the peak values and the time period.