Basic Physics II Evidences - DrJJ - UiTM

CONFIDENTIAL6AS/APR 2008/PHY407qv0 IF qvB 2rand pointing downwards.(4+7+10=21 marks)QUESTION 4a) i) Faraday’s Law of electromagnetic induction states that emf will be induced in a coilwhenever there is a change in the magnetic flux through the coil and the induced emfis proportional to the number of turns in the coil and the flux change in a second.ii) Lenz’s Law of induced current or induced emf (voltage) states that the inducedcurrent is in a direction so as to induce a magnetic field in order to oppose the fluxchange in the coil. If the flux is decreasing such as the south pole of a bar magnet isleaving the coil, then the induced magnetic field must be in such away to attract andprevent the south pole of the bar magnet from leaving. Hence the induced currentand emf must follow this induced magnetic field.(4+4=8 marks)b) For each of the configuration in Figure 6, use Lenz’s Law to indicate the polarity of theinduced magnetic field, the induced emf and the induced current.NSSNSNSNNII+-I-SS+ACsourceNearby Coilconnected to aresistorRIN(3+3+2=8 marks)c) i) Self-inductance is the induction of current and emf in a coil whenever there is achange in the current of that particular coil and not due to flux change from othersources.Mutual inductance is the induction of current and emf in a coil due to flux changescaused by another coil nearby.© Hak Cipta Universiti Teknologi MARA CONFIDENTIAL