Basic Principles of Electromagnetism

C h a p t e r 4 | 94Solution 4.1When a conductor moves in a magnetic field it will have an emf induced in itbut this emf can only produce a current if there is a closed circuit. Induced emfE = Blv = (1.25)(300/1000)(4)(a)If the ends of the conductor are open circuit, no current will flow eventhough 1.5 V has been induced.(b)From Ohm’s lawE 1.5I = = 75mAR 204.5.2 Lenz’z LawThe direction of an induced emf is always such that it tends to set up a currentopposing the motion or the change of flux responsible for inducing that emf.This effect is shown in Figure 4.9.Source: Pengajian Kejuruteraan Elektrik dan Elektronik, Cetakan Pertama 2000 by Mohd. Isabin IdrisFigure 4.9: Bar magnet move in and move out from a solenoidBasic Principles of Electromagnetism