cape june2011 physics unit2.ex

8/13/2019 CAPE June2011 Physics Unit2.Ex

1/12


2/12

igare I shows nrro beam of electrons traelling at speed, n directed intoa uniform eectric held hcti4een two oppocitely charged parallel plates placed a distance,I apart. fhe top plate is at a positive potential, V. relative t the o w r plate. magneticfield is now applied perpendicularly to the direction of the electric field between the platesmd the deflection of the beam is canceile

Figure (c)1 State the direction of the magnetic field

ii y considering the forces on EACH electron, show that the macnetic flux densityis given by

vdlp rt i n lq rv


3/12

iii Given that 3500 V v 1 rn s mdd mm Lalcu ite them igneticflux density of the magnetic field

ccV

bI3io rr5 Jm 3

rnarksl

is the magnetic flux density is w doubled the distance between t plates thenadjusted that no deflection occ urq. Ilculate the new distanceUn QO tb O

B j

marksl


4/12

CAPE PHYSICS 2011Paper 02 U T 2 EXEMPLARS

MODULE 1Question 1

Although this candidate showed a very good understanding of the material necessary to answer thisquestion the response could have been improved in the following areas: In part a i , the candidate should have provided a more complete definition of the magnetic flux

density by including that the field and current must be perpendicular In part b , the catapult could have been drawn more accurately The f ie ld lines from S

between the magnets below the wire should have been more concentrated and have a morepronounced dip.

In part c , had the candidate recalled the relationship B c and recognised that if B is doubledthen d has to be halved the solution could have been more succinctly presented in one or two lines


5/12

2 a i \Vhat does the trm bist bie m n hen used in rebrence to an electrontc ciauit?cs v ct i

[lmarkjii Figure 2 shows a quad NOR circuit board with es to show the output ofeach gate. It is connected to 6 V battery.

Figure 2 a

3

ocLcn t5 s o fssws sruaai cia

5

6 Vr2

r il

cquenceof inputs outputsDraw connecting wires on th diagram toshow the construction of an SRuiy Row with clearly, marked inputs I and andoutputs and friend asks you to demonstrate bow thiscircuit acts as n electronic qjerhapsa, part of a bunslar alarm. Complete thesequential trutH table on me rigHt and use tt

to assist you in describing the connetionsto sour uo

x

l 0 0

0 o0 0 0


6/12

Fi ure b hows v ise forms A and B is puts fl I gic LII rcs fltmutput aveiorin D, is sIC vn

B

Figure bDraw the truth table for he circuit and boric state the equivalent logic gate for t circuitfruth table.

t i_I

uivalent iOUC g


7/12

\ kilz square wave of amplitude V is input into one input of an XOR uate uhile theother input is grounded n oscilloscope is used to view the output waveformI What is the frequency of rhe XOR output l

mark f the same frequency is input but the other input to the XOR is tied to 5 V whatis the frequency of the output

tmriii rhe same square wave is applied to one input of logic gate P while the other Input grounded See Figure c below. T he output waveform is a fl t line t State t name of logic gate P and use a truth table to explain your anser

Figure c


8/12

CAPE PHYSICS 2011Paper 02 UNIT 2 EXEMPLARS

MODULE 2Question 2Overall, this candidate provided a good response, however, no marks were awarded for part a , sincethe candidate failed to define the term bistable as a circuit having two different stable outputs for oneparticular input state.In part a ii , the candidate correctly connected two of the four NOR-gates althoughn 2 inputscould h ve been drawn to indicate connections to the 6 V and 0 V rails as well.The sequential truth table was correctly drawn but the description of the burglar alarm features couldhave been expanded to describe what would happen if the burglar tried to close the window after thealarm was turned on . This should have been related to the table and the fact that needed to bechanged to reset the alarm nd that changes tooul not affect the alarm rows 3, 4, 5, 6 so thealarm remains ON. rt b was correctly done.For parts c i nd ii , the candidate correctly stated the frequencies as 1 K z regardless of which inputthe K z square wave was applied to. rt c iii was cle rly explained and the candidate correctlyidentified the logic gate P as an AND gate.


9/12

9

6. a) i ) Explain what is meant by nuclear fis sion.ii) Sketch a graph to show how the binding energy per nuc leon varies with the mass

number of the nucleus. Show on the graph the app rox imate positions ofcarbon- 12and uranium-235.ciii) list your graph to exp lain why energy is released when a heavy nucleus undergoesfission.

6marksb) The fission oft kg of uranium-235 releases as much thermal energy as 50 000 kg of oil.30 Mi of energy is released when kg of oil is burned.

Calculate the mass of fue l used per day, in EACH case, in a 1 MW power stationwhich is only 25 effic ien t and which usesi) oilii) uranium. 8 marksj

c) Hence comment on the sus tainabi lity of using oil as an ene rgy source for the next century. mark Total 15 marks

GO ON TO T NXT PAGE223S 2 fC PE 2011


10/12

2

\ou MUST write the answer to Question 6 here6. a fLLfz4iS?LQ

o Sin eT ri

r r7

Joi7 i r rf L

S Littrio } ii

LLEflul4itLie iJi _ _

Tkz Si i hi bint? j f2e,- nuthm decnoies iiflCrWS1u1 t1f JYU HLU

tt m 7

bif 9irj r

ft i eCeI

j

j iJR iiF


11/12

b Id ne4d b th2 h 1ooo/1LV

QO pzi ilw L1L procL o ;i 0

citt ptz o;fr ccTit fr e ec to pt eriit

fl pwer ned4 abtt 1 lizz cL each dayH Ur prO e :c4 o { oJ

/

tAr ettd +0m C1O

c Oi7fiUrin pmer it iIi

iv ji opr vdeI nj t


12/12

CAPE PHYSICS 2011Paper 02 UNIT 2 EXEMPLARS

MODULE 3Question 6While the description of nuclear fission in part a I is cler the candidate incorrectly stated thatduring this process binding energy is released rather than energyOverall the candidate provided a good sketch of the graph is good However one small error was thatthe point representing carbon 12 was positioned too low on the curveAlthough the candidate provided a comprehensive explanation to part a iii , the response could havebeen improved if the candidate had specifically stated that during the fission of a heavy nucleus lessmass energy is released Additionally had the candidate included the equation n in theexplanation this would also have strengthened the responseThe calculations in part b were wll laid out and used the correct substitutions hence the candidatewas awarded maximum marks for this portion of the questionIn part c, the candidate correctly used the values from the calculations in justifying why it was notsustainable to use such a large amount of oil on a daily basis

cape june2011 physics unit2.ex

Documents