20.6b Ex3 MJ20 P41 Q9 Disc Torque & Solenoid Induction | May/June 2020 | CAIE 9702 Physics

9702/41/M/J/20: (a) A coil of wire is situated in a uniform magnetic field of flux density B. The coil has diameter 3.6cm and consists of 350 turns of wire, as illustrated in Fig. 9.1. The variation with time t of B is shown in Fig. 9.2. #9702s20p41 #Lv3 #A2solenoidCoilsP4 #A2inducedEmfGraphP4 #A2varyingBfieldP4 (i) Show that, for the time t = 0 to time t = 0.20s, the electromotive force (e.m.f.) induced in the coil is 0.080V. (ii) On the axes of Fig. 9.3, show the variation with time t of the induced e.m.f. E for time t = 0 to time t = 0.80s. #A2eddyCurrentsP4 (b) A bar magnet is held a small distance above the surface of an aluminium disc by means of a rod, as illustrated in Fig. 9.4. The aluminium disc is supported horizontally and held stationary. The magnet is rotated about a vertical axis at constant speed. Use laws of electromagnetic induction to explain why there is a torque acting on the aluminium disc. #A2magneticInduction Playlist:    • Ch20 Magnetic Induction (Part 2) | CAIE 97...   MJ20 Paper Discussion Playlist:    • 9702 MJ20 Papers CAIE Physics   Instagram Pocket Guide (  / etphysics  ) More Resources (https://9702-physics.blogspot.com/) Support us! (  / etphysics  ) Tuition/Tutoring inquiries: Email: [email protected] Whatsapp: https://wa.me/60126679171 9702_s20p41 May/June 2020 #CambridgeALevelPhysics