Quiz on ElectromagnetismName: ________________________1.This diagram shows the magnetic field of a. two wires at Y and Z both carrying electric current into the aerb. two wires at Y and Z both carrying electric current out of the aerc. a wire Y carrying current into the aer anda wire Z carrying current out of the aerd. a barmagnet with N ole at Y and ! ole at Ze. a bar magnet with ! ole at Y and N ole at Z".#hen the a.c. suly to the coil is switched on and left on$ the iron bar will..a. stay at the same height and %ibrateb. be reelled uwards from the coil and then remain stationaryc. mo%e down towards the coil and then %ibrate slightlyd. do not mo%e at alle. mo%e down towards the coil and then u again to its starting oint&.The three lines mar'ed ( in the diagram are a symbol fora. a caacitorb. insulationc. a soft iron cored. a ermanent magnete. a magnetic field).#hen current flows through the coil shown in the abo%e diagram$ in which of the following ways is the iron magnetized*a. North ole at +$ !outh ole at ,b. North ole at ,$ !outh ole at +c. No oles at + and ,d. North ole at +$ North ole at ,e. !outh ole at +$ !outh ole at ,-.#hich one of the following grahs best shows the %ariation of the magnetic flu. density along the a.isof a current carrying solenoid /the solenoid osition is shown on the grah0*1.#hen the magnet rotates as shown an alternating e.m.f. is generated in the coil.2f the seed of rotation is doubleda. the %oltage increases and the fre3uency is reducedb. the %oltage increases and the fre3uency doublesc. the %oltage stays the same and the fre3uency doublesd. the %oltage decreases and the fre3uency is reducede. the %oltage decreases and the fre3uency doubles.4. 5 transformer has 166 turns on its rimary and 1666 turns on its secondary.2f a -6.7z$ 166. 8 outut is seen at the secondary$ then thea. fre3uency at the rimary is -.6 7zb. %oltage across the rimary is 16.6 8c. current in the secondary is 16 times the current in the rimaryd. secondary dissiates more energy than the rimary9.The unit for electrical ower is the a. :ouleb. wattc. ohmd. Newton;.The current direction in the rotating coil of a simle d.c electric motoris re%ersed e%ery half re%olution to a. re%erse the olarity of the field magnetb. re%ent corrosion of the brushes.c. maintain the direction of rotation of the coild. ro%ide an a.c outut from the motor16.#hich of the following statements iss law of electromagnetic induction may be stated as ?the induced effect in a circuit is in such a direction as to oose the change which roducing it@.The hrase ?the change which is roducing it@ means a change in thea. resistance of the circuitb. temerature of the circuitc. material from which the circuit is maded. magnetic flu. /field0 lin'ed with the circuit