cape 2003 unit 2 paper 1
DESCRIPTION
exam paperTRANSCRIPT
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- 4 -
2. (a) Define EACH of rhe following terms:
(i) Magnetic flux:
[1 mark ]
(ii) Tesla:
[1 mark ]
(b) State
(i) Faraday's Law
[1 mark ]
(ii) Lenz's Law.
[1 mark ]
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(c) Two conducting rods are joined
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at right angles to each other as shown in Figure l.
Conductingbar
o Conducting rods
o r .
. Figure I
A conducting bar in contact with the rods starts at the vertexvelocity (v) of 4-20 m s-r arong them as shown. A magneticis directed perpendicularly our of the page.
Find the
(i) area of the triangle which is formed at 2 seconds by the conducting bar andconducting rods
[2 marks](ii) magnetic flux through the triangle at seconds
(iii) electromorive force (e.m.f.) induced in rhe
[2 marks]
moving rod at 2 seconds.
[2 marksl
Total l0 marks
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and moves with a consrantfield of magnitude 0.450 T
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3. (a) Write an expression for the total resistance, Rr, of three resistors Rt, Rz and R3, in
parallel.
[1 mark I
(b) State Ohm's Law.
ll mark I
(c) Explain the difference between the electromotive force (e.m.f.) and the terminal potentialdifference (p.d.) of a battery.
[2 marks]
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(d)
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A set of measurements were made using the circuit of Figure 2.
Figure 2
Table I below shows some of the results obtained.
R v I
0 0 O.15 A
300 a r 0 voo
Thble I
Fill in the blank spaces in rhe tabre with the missing data.
[6 marks]
Total 10 marks
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4. (a) Explain what is meant by EACH of the following:
(i) P-type semiconductor
(ii) N-rype semiconductor
t i i i ) Doping, as appl ied to semiconduclors
(iv) Depletion region
O) Suggest ONE application of a p-n junction diode.
lL mark I
[1 mark I
[1 mark ]
[1 mark ]
[1 mark ]
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(c) Figure 3 shows a combination of two silicon diodes in a circuit.
Figure 3
The characteristic I - v curve for the diodes is shown in Figure 4.
uA z.s2.0
1.5
1.0
0.5
00 0.2 vlv
( i) Calculate the
a ) V i =
voltage, 7r, when
[2 marksJ
b) Vr = - 10-0V.
[1, mark ]
1000 o
vo
2.0 v -r -1- z.o vI
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- 1 0 -
(ii) Sketch the output when V, = 10 Sin 0)t, where c0 = 100 rad s-1, includingappropriate numerical values on the scales.
[2 marks]
Total 10 marks
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(a)5 .
t l
In the space provided below sketch a typicalamplif ier.
gain frequency curve for an operational
[3 marks]
(b) What is meant by a 'virtual earth' rn an operational amplifier circuit?
[1 mark ]
(c) State ONE effect of positive feedback in an operational arnplifier circuit.
[1 mark ]
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(d)
. 1 , 2 -
Figure 5 shows a cascade amplifier circuit-
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Figure 5
Calculate the
(i) net gain of the circuit
[4 marks]
(ii) output voltage, Vr, when Vi = 0.01,V.
[1 mark ]
Total 10 marks
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(a)6.
1 3 -
(i) Arithmetic operations are usually performed by adders. A half adder circuitis used to add the l 's column in binary addit ion. Write the truth table for ahalf-adder.
[2 marksl
You are provided with an Exclusive-OR (EX-OR) gate and an AND gate fordesigning a half adder circuit. Draw a circuit diagram to show how these couldbe arranged.
[2 marksJ
( i i )
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- 1 4 -
(b) Draw a circuit diagram to show how the NAND gares could be used to build a flip-flop.
[1 mark ]
(c) Write the truth table for the circuit shown in Figure 6, indicating the output at X, Y andZ"
Figure 6
[3 marks]
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(d) Draw a simple logic circuit to represent the rruth table below in which A and B areinputs and X is the outpur.
A B X0 0 00 1 0r 0 t
[2 marks]
Total 10 marks
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1 6 -
7. (a) State THREE experimental facts about the photoelectric effect which support theparticulate (photon) model of light.
[3 marks]
(b) When ul t raviolet l ight is incident on an insulatecl metal p latc, thc plate emits electronsfor a while and then stops.
Explain why the process'eventually stops.
[1 mark ]
(c) The energy level scherne for a newly discovered one-electron element is shown inFigure 7. The electron is in its ground state.
n = 4
n = 3
n = 2
n = l
-2 eY
-5 eV
-10 eV
-20 eV
Figure 7
(i) Determine the amount of energy it will take to ionize an electron from theground state.
[1 mark 1
(ii) State what will happen if a 6 eV photon srrikes the atom.
[1 mark 1
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(d) An electron makes a transition from the n = 3 state to the n = I state.
(i) Calculate the frequency of radiation emitted.
[2 rnarks]
(ii) Calculate the wavelength of radiation emitted.
l l mark 1
(iii) In which region of the electromagnetic spectrum would this radiation be found?
[1 mark ]
Total 10 marks
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8.
- 1 8 -
(a) (i) Explain the principle by which a continuous X-ray spectrum is produced.
[2 marksJ
Why is a vacancy in an inner electron shell usually required for an atom to emitan X-ray photon?
(ii)
(b) A beam of X-rays, of intensity /r, is incident on a slab of materialabsorption coefficient prr, as shown in Figure 8 a.
[2 marksJ
of thickness x, and
(i)
< - x r €
Figure 8 a
Write an expression for the emerging intensity, /, in terrns of /p, 1t1 and x,.
[1 mark I
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(ii)
_ 1 9 _
A second slab of material, of thickness x2 and absorption coefficient pr, isplaced alongside the first slab as shown in Figure 8 b.
* tr-> (,-- t r-
Figure 8 b
Show that the Intensiry, /, is given by
I = Io e-(ts,t, * Frtr)
[3 marks]
= 8.0 rn-I,
a)
b) Calculate the value of / where Io =
xt = 2.0 mm, p2 - 4.0 m-l , x2 =500 Wm-2, ltt
4r0 mm"
[2 marksl
Total 10 marks
* r r _ >
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(a)9,
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Explain what is rneant by EACH of the following tenns:
(i) Nuclear fission
[1 mark J
(ii) Nuclear fusion
[1 mark J
(iii) Binding energy
(b)
[1 mark ]
"r1u. How many of EACHThe nucleus of an atom of uranium can be represented byof the following particles are there in the nucleus?
(i) Protons
[1 mark J
(ii) Neutrons
lL mark J
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(c) An induced fission reaction is described by the following equation.
in * '71ru - 23n6rtJ* -+ tflna + 3?tt * 3!n + E
Masses:
'llru = 235.0439 u
'!|n" = 140.9141 u :
t2*, = 9l .9262 u
fn = 1.0087 u
I u = 931.5 MeV/cz
Calculate
(i) the energy E, in eV released during the reaction
the energy, in eY of EACH neutron producbd in the reaction.
END OF TEST
[4 marks]
(ii)
ll. mark J
Total L0 marks
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