Unit 8J (Magnets and electromagnets) Question No. 1(01) 3 2(05) 3 3(99) 4 4(97) 4 5(05) 4 6(05) 6 7(95) 6 8(97) 7 Level 4 6 4 5 5 6 5 6 5 5 6 7 3 Mark 9(99) 7 10(05) 7 11(01) 7 12(01) 8 13(97) 8 Rainford High Technology College 1 1 mark (c) %riction at the pivot made the cat-flap s&"eak. so that it does not blow open in the wind. door c a t . 1 mark (ii) Add a label to the diagram to show the pivot of the cat-flap. .fla p m a g n e ts # $ b o tto m o f d o o r (b) Ali "sed two bar magnets to keep the cat-flap closed. door c a t .enn. 1 mark !hen the cat has gone thro"gh the cat-flap. Ali made a cat-flap to fit into a door. Rainford High Technology College . label both the #orth and $o"th poles on the magnet in the cat-flap. . !hat co"ld Ali p"t on the pivot to make the friction less' ((((((((((((( 1 mark )a*im"m + marks 2. Label it . the weight of the cat-flap makes the flap close. draw an arrow to show the direction of the force of the cat’s head on the cat-flap. On the diagram above.Unit 8J (Magnets and electromagnets) 1.f la p b o tto m o f d o o r (a) (i) On the diagram above.dropped her torch down a drain. ..................................................enn... 0 marks (ii) 1n the space below......... .p"t the mirror to see the torch' /ick the correct bo*............. ... (i) On the line below each diagram... not to scale (a) (i) ............................ give the name of the part... 1 mark (ii) !hat happens to the light from the torch when it hits the mirror' . draw a circ"it diagram to show how these three parts are connected in a torch...... 1 mark ma*im"m 2 marks Rainford High Technology College 0 .........co"ld not see it....... At which angle sho"ld .................................enn....................................... ..enn....................Unit 8J (Magnets and electromagnets) /he torch was still switched on b"t ... 1 mark (b) /he diagrams below show the s-mbols for three parts of the torch circ"it..........lowered a mirror into the drain and placed it at position ........... ............. $"ggest a reason for this.............................................................................................................. /hen she holds the $o"th pole of the bar magnet near the same end of the block of metal.. 1 mark (b) !hat metal co"ld 3achel’s block be made from' ((((((((((((((((((((((((((((((((( 1 mark (c) 3achel p"ts the block of metal in a thin plastic bag......................attract..................................... 1 mark )a*im"m + marks Rainford High Technology College + .......................................................................................................... . N bar m agnet 3 a c h e l4s b lo c k o f m e ta l S $he holds the #orth pole of the bar magnet near one end of the block of metal.................. 1 mark (d) 3achel p"ts the bar magnet into a pile of coins...............................attract...... !hat effect............................ if an-......... .................................................. ....... (a) 5*plain how this shows that 3achel’s block of metal is not a permanent magnet....................... /he......................... 3achel has a small block of metal......................................................................................................... $he wants to know if it is a magnet...... ......................................Unit 8J (Magnets and electromagnets) 3... ......................................... Again the........ $ome of the coins are attracted to the magnet b"t some are not................... will the bar magnet now have on the block' ......................................... /he drawing shows a to.shark. 1n which direction will it move' .repel the "nknown pole is #. 1 mark )a*im"m 9 marks 5.1f the poles attract. # m agnet A m agnet 6 $ /he north pole and so"th pole are shown on magnet A. beca"se the poles will repel. "sing magnet A. /he poles are not shown on magnet 6. )agnets : and . 8e gives the tr"ck a p"sh so that it rolls along the table. (a) /he diagram shows two bar magnets. w a ll m agnet fi* e d t o tr" c k m agnet f i* e d t o w a ll w o o d e n tr" c k t a b le $ # # $ . the known pole is $.ames removes the magnet from the wooden tr"ck. 1f the. /hen he lets go of the wooden tr"ck. 1 mark (c) . 7escribe an e*periment -o" co"ld do. "t the north pole of magnet A to an "nknown pole of magnet 6.Unit 8J (Magnets and electromagnets) 4.ames holds the wooden tr"ck so that it does not move. 0 marks (b) /he diagram shows a wooden tr"ck near a wall. Rainford High Technology College 9 . !hat effect will friction have on the speed of the tr"ck as it rolls along' %riction will stop the tr"ck./he tr"ck will not move towards the wall. to find which end of magnet 6 is the north pole and which is the so"th pole. /here is a strong magnet fi*ed to the wall and a strong magnet fi*ed to the front of the wooden tr"ck. make the shark <float’ above the plastic base. 1 mark Rainford High Technology College 2 . !hen she releases her finger. the shark goes down. attract cancel repel /he to. !hat happened to the shark when she removed her finger' 1f she presses down the shark. 1 mark (b) (i) =hoose a word from the list below to complete the sentence. 1 mark (ii) $ophie pressed down on the tail of the shark with her finger. the shark floats.Unit 8J (Magnets and electromagnets) (a) On magnet :.shark <floats’ beca"se the magnets repel each other. write the letters # and $ to label the poles of the magnet. shark and meas"red the distance between the two magnets. weight added to the toy shark (N) >."p. 1 mark ma*im"m 9 marks Rainford High Technology College ? .1 >. 8er res"lts are shown below..Unit 8J (Magnets and electromagnets) $ophie added weights to the to. the distance between the magnets decreased.shark increased. 1 mark distance between the magnets (mm) 2 + 0 (d) $ophie t"rned the magnet in the plastic base the other wa.0 =omplete the sentence below. !hat happened to the shark' /he magnets attract and the shark fall down. >. As the weight on the to. Ale* makes an electromagnet.Unit 8J (Magnets and electromagnets) 6. /his is her prediction. /he t"rns of the coil of wire 1 mark (ii) @ive one factor she sho"ld keep the same. he more t!rns o" wire aro!nd the iron nail the stronger the electromagnet becomes. )ore iron nails picked "p. the stronger the electromagnet. $he "ses the electromagnet to pick "p some steel paper-clips. $he connects the wire to a power s"ppl-. 1 mark Rainford High Technology College A . (a) (i) @ive the one factor she sho"ld change as she investigates her prediction. $he winds ins"lated wire aro"nd an iron nail. /he power of s"ppl1 mark (iii) 7escribe how she co"ld "se the paper-clips to meas"re the strength of the electromagnet. /he diagram shows an electromagnet "sed in a door lock. 1 mark (ii) @ive a reason for -o"r choice. 1 mark (c) (i) !hich siBe paper-clips wo"ld Ale* "se to make her res"lts more acc"rate' /ick the correct bo*. !hat wo"ld an odd res"lt s"ggest' Odd res"lt will contradict her prediction. 1 mark ma*im"m 2 marks #. #"mber of coils increases the strength of the electromagnet. 6"t her prediction was tr"e with the e*periment. the more acc"rate the res"lts will be. /he smaller the paper clips.Unit 8J (Magnets and electromagnets) (b) Ale* wrote a report of her investigation. p"sh s w itc h ir o n c o r e fi* e d to d o o r fra m e c o il s p r in g door fra m e door ir o n b o lt Rainford High Technology College C . ..... /he spring rebo"nds and the door is locked..... /he switch is released.. what will happen to the steel sheet' /he steel sheet will attract to the iron electromagnet......aro"nd. 1 mark Rainford High Technology College 1> ............ marks )a*im"m 9 marks $...... 1 mark (ii) /he p"pil opens the switch again.. /he door lock is opened........ 5*plain in detail how this happens... what difference wo"ld this have made to -o"r answer to part (i)' /he wa....... t h in s p r in g s te e l sheet e le c tro m a g n e t case (a) (i) !hen the p"pil closes the switch.... /he c"rrent passes thro"gh the iron core and goes thro"gh the coil of wire..... ..steel sheet.. 1 mark (iii) 1f the p"pil had connected the batter... /here is no c"rrent passing thro"gh..ro"nd..... /he device acts like a small speaker......... 5*plain in detail how this happens........ /he c"rrent will p"sh the spring forward and open the iron bolt.will be the other wa. .....and switch to the electromagnet as shown.the other wa. ...... A p"pil fi*es a small electromagnet close to a thin spring..... 0 marks (b) /he switch is released and the door locks. $he connects a batter..... !hat will happen to the steel sheet now' /he steel sheet will not be attracted to the electromagnet......Unit 8J (Magnets and electromagnets) (a) /he p"sh switch is closed and the door "nlocks..... .which switches the c"rrent on and off 1>>> times each second. $he connects the electromagnet to a power s"ppl. s te e l s h e e t v ib r a t e s a n d m akes a so"nd po sw on 1> ea w e r s " p p lit c h e s c " r r e n t a n d o ff > > t im e s ch second (i) $he then adD"sts the power s"ppl. !hat difference does this make to the pitch of the so"nd' @ive a reason for -o"r answer. marks (ii) /he p"pil now adD"sts the power s"ppl. the pitch becomes higher. 1 mark )a*im"m 2 marks Rainford High Technology College 11 .so that the c"rrent is switched on and off 0>>> times each second.this makes the so"nd lo"der.so that the c"rrent is larger. A so"nd with bigger amplit"de has a lo"der so"nd. A larger so"nd has bigger amplit"de. /he more times -o" adD"st the power s"ppl-.Unit 8J (Magnets and electromagnets) /he p"pil removes the batter. /he steel sheet vibrates and makes a so"nd.and switch. 5*plain wh. -o" will get an electric shock.set "p the circ"it shown below. 1f -o" to"ch them. 6rass is not magnetic and there is still no c"rrent passing thro"gh. /he rods will repel. A reed switch is made of two iron strips inside a glass t"be.spring apart again when the magnet is removed. Rainford High Technology College 1. !hat. if an-thing. 1 mark (b) One of the two iron rods is taken o"t and replaced with a brass rod. marks (ii) /he switch is then opened to break the circ"it.this happens. !hen there is no c"rrent flowing thro"gh the electromagnet the rods have no strength to attract. happens to the two iron rods' /he two iron rods will be electric. (a) !hen the switch is closed. . marks )a*im"m 9 marks 1&. will happen to the rods when the switch is closed' 5*plain -o"r answer. /he diagram shows a rectang"lar coil and circ"it.Unit 8J (Magnets and electromagnets) %. 1t has two iron rods in it.repel.are free to move. !hat. /he iron strips close together when a magnet is bro"ght near. the. 1nstead. (a) 8ilar. /he. . (i) 5*plain wh. /he rods are parallel and to"ching. if an-thing. /he. . the two rods move apart. /he rods are parallel and to"ching. co"ld increase the strength of the electromagnet.Unit 8J (Magnets and electromagnets) $he tried to close the reed switch "sing an electromagnet. marks 8ilar. label the poles of the iron strips when the c"rrent was reversed. Rainford High Technology College 10 . . Ese a magnetic material for the core. 'n the diagram below.increased the strength of the electromagnet. 1 1ncrease the n"mber of coils. . /he iron strips were magnetiBed as shown below. (i) @ive two wa-s 8ilar. /he reed switch closed. $he closed switch 5 b"t the electromagnet was not strong eno"gh to close the reed switch. $he reversed the c"rrent in the coil of the electromagnet. 5*plain wh. 1 mark (ii) $he replaced the reed switch with a piece of copper wire. /he p"pil t"rns the magnet aro"nd so that the $o"th ole is nearest the coil. if an-. will this have' /he $o"th ole will be attracted towards the coil.more c"rrent flowed thro"gh the b"lb when the reed switch was replaced with copper wire.and it is fle*ible to stretch to a long distance 1 mark ma*im"m 9 marks 11. c o il # $ m agnet /he magnet is attracted towards the coil. 1 mark Rainford High Technology College 1+ . (a) A p"pil makes a small coil of copper wire and passes an electric c"rrent thro"gh it.Unit 8J (Magnets and electromagnets) 1 mark (b) (i) 1ron and steel are both magnetic materials. /he c"rrent thro"gh the b"lb increased. /he p"pil places a small magnet near the coil. !hat effect. 1ron acts like a permanent magnet. =opper is good cond"ctor of electricit.the strips m"st be made of iron and not steel. $teel contains other materials incl"ding iron. 1ron is more magnetic than steel. 5*plain wh. !h. s c a le s tra w p iv o t m agnet p a p e r c lip c o il not to scale (i) /he paper clip is "sed to balance the weight of the magnet.from the pivot than the magnet is' Rainford High Technology College 19 .Unit 8J (Magnets and electromagnets) /he p"pil "ses the coil and the magnet to make a simple ammeter to meas"re the c"rrent thro"gh a b"lb.the paper clip is f"rther awa. (((((((((((((((((((((((((((((( (((. ((((((((((((((((((((((((((((((( ((((((((((((((((((((((((((((((( ((((((((((((((((((((((((((((((( ((((((((((((((((((((((((((((((( .(((((((((((((((((((((((((((((( (((. 5*plain wh. 1 mark (ii) 5*plain how a c"rrent in the coil makes the straw pointer move.the magnet. ((((((((((((((((((((((((((((((( ((((((((((((((((((((((((((((((( ((((((((((((((((((((((((((((((( . marks Rainford High Technology College 12 . marks (iii) /he p"pil places a piece of soft iron in the middle of the coil.Unit 8J (Magnets and electromagnets) aper clip can be attracted. (((. 7escribe and e*plain how this will affect the reading on the scale when the same c"rrent flows thro"gh the coil.(((((((((((((((((((((((((((((( (((.this happens.(((((((((((((((((((((((((((((( . it alwa-s moves back to the position shown in the diagram. p iv o t N N S h o rs e s h o e m agnet S bar m agnet (a) !henever Anita tips the bar magnet. b. Anita has arranged a horseshoe magnet with a long bar magnet pivoted above it. marks )a*im"m 2 marks 12. ((((((((((((((((((((((((((((((( Rainford High Technology College 1? . # $ Anita winds a coil aro"nd each end of the horseshoe magnet as shown below. 5*plain -o"r answer.Unit 8J (Magnets and electromagnets) (b) !hen a c"rrent is passed thro"gh a coil. it prod"ces magnetic poles as shown in the diagram below. p iv o t N N S S bar m agnet h o rs e s h o e m agnet (i) 7escribe what will happen to the bar magnet when she closes the switch. .....................Unit 8J (Magnets and electromagnets) ((((((((((((((((((((((((((((((( ((((((((((((((((((((((((((((((( ((((((((((((((((((((((((((((((( ((((((((((((((((((((((((((((((( ((((((((((((((((((((((((((((((( 0 marks (ii) Anita reverses the batter-...... ...... 8ow wo"ld the pattern on the tape be different if the tape were moved past the recording head more &"ickl-' ..........with a power s"ppl...........is shown in the diagram below............... 1 mark (b) /he direction of the c"rrent is changed at reg"lar intervals...... (a) As the tape moves past the recording head.....................which changes the direction of the c"rrent ever.. /he tape is Rainford High Technology College 1A ...... /he direction of the c"rrent is changed at reg"lar intervals............ $"ggest what happens to the bar magnet..... ((((((((((((((((((((((((((((((( ((((((((((((((((((((((((((((((( 1 mark (iii) Anita replaces the batter.... ((((((((((((((((((((((((((((((( ((((((((((((((((((((((((((((((( 1 mark )a*im"m ? marks 13......... One wa. /he magnetic particles in the section of tape "nder the recording head line "p with the field...............second...... different sections of the tape become magnetised........................................................... c o il r e c o r d in g head m a g n e t is e d a re a o f ta p e ta p e /he recording head prod"ces a magnetic field.... 7igital information can be stored on magnetic recording tape in several different wa-s................... $"ggest what happens to the bar magnet............ ........... ................................. ....................................................................................................Unit 8J (Magnets and electromagnets) moved past the recording head at a stead........... ................................................................... ............ /he gap between the poles of the recording head is made m"ch bigger........... $"ggest two effects this might have on the pattern on the tape.......................................................... 1 ............................................................ marks )a*im"m 0 marks Rainford High Technology College 1C ............................................ .......................................speed.........