1

SECTION A
Multiple Choice: This section comprises FIFTY questions. Choose the
corresponding letter of the correct response to each question below. Each question is
worth 1 mark

1. Doubling both the voltage and 5. From which of the following is electricity chemically
resistance in a parallel or series circuit will produced?
cause the current flow to (A) photo cell
(B) Carbon
(A) double (C) Batteries
(B) halve (D) Generators
(C) remain unchanged
(D) quadruple 6. In order to connect Battery X and Battery Y in
parallel, their terminals should be connected
(A) +X with +Y and –X with –Y
2. Which of the following materials has (B) +X with –Y and –X with +Y
a negative temperature coefficient? (C) –X with +Y
(D) –Y with +X
(A) Brass
(B) Silicon 7. It is advisable, not to use Water for
(C) Iron extinguishing electrical fires because
(D) Copper water

3. The r.m.s value of a sinusoidal (A) may cause corrosion

alternating voltage is (B) may transmit shock to the user
(C) may damage wire insulation
(A) 0.318 peak value (D) will not extinguish the fire
(B) 1.414 peak value
(C) 0.707 peak value
8. Which of the following is true for
(D) 0.77 peak value
TWO resistors connected in parallel?
4. (A) The current flow through each
resistor is the same.
(B) The voltage across each resistor is
the same.
(C) The combined value of the resistors
is equal to the sum of the
individual values.
(D) Each resistor has the same
In the above diagram Lamps R and S resistance value.
are identical.
A volt meter connected across Lamp S
should read

(A) one quarter of the applied voltage

(B) one third of the applied voltage
(C) one half of the applied voltage
(D) the total applied voltage

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9. Four 24V batteries are first connected in 14.

series and then in parallel. The total
voltage is
(A) Four times greater in parallel than in
series
(B) Four times smaller in series than in
parallel
(C) The same in both connection
(D) Four times smaller in parallel than in Which of the following would be true for
series any value of current flowing in the above
circuit?
10. What is the expected current (A) V1 = V2
drawn by an electric cooker rated (B) V1 < V2
at 12KW/230 volts? (C) V1 > V2
(A) 19 Amps (D) V1 ~ V2
(B) 48.5 Amps
(C) 52.17Amps 15. The rate at which work is done is
(D) 95 Amps
referred to as
(A) Energy
11. An open circuit has the effect of (B) Torque
(C) Power
(A) Infinitely high resistance and (D) Current
zero current
(B) Zero resistance and 16. An electric stove rated at IKW, 200V,
excessive current is accidentally connected to a 100V
(C) Excessive current and supply. What power would it now
excessive heat develop?
(D) Zero resistance and excessive
voltage drop (A) 250W
(B) 500W
12. A secondary cell is one which (C) 800W
(A) has an internal resistance of 0.5 (D) 1000W
ohms
(B) cannot be recharged 17.
(C) when in use will not deteriorate
(D) Can be recharged

13. Silver is a very good conductor of

electricity. It has
(A) low permittivity
(B) high conductivity
(C) high resistivity The circuit above represents a
(D) low permeability (A) bell circuit
(B) battery driven machine
(C) lamp dimmer
(D) potentiometer circuit

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22. The power dissipated by a 50Ω resistor

18. which is connected to a 24V d.c. supply is
(A) 10.00w
(B) 11.52w
(C) 54.00w
(D) 360.00w

23. A variable resistor can be connected

as a potentiometer and as a
(A) varactor
(B) rheostat
(C) fuse
(D) switch
The ratio of the current in circuit ‘A’ to
that of circuit ‘B’ is
24. External energy such as heat, light or
electricity can cause electrons in the
(A) 1:5
valence shell to become
(B) 2:1
(A) charged
(C) 5:1
(B) stationary
(D) 5:2
(C) trapped
(D) free
19. The voltage at the end of a supply
line was only 90% of the supply voltage.
25. The internal resistance of a cell having
This could be due to the
an e.m.f. of 2V and a terminal voltage of
1.8V when supplying a current of 20A is
(A) cable being too large
(A) 0.01Ω
(B) cable overheating
(B) 0.05Ω
(C) Supply voltage being too low
(C) 0.10Ω
(D) resistance of the cable being too
(D) 0.15Ω
high
26. How many amperes of electric
20. The formula for quantity of
current are equivalent to 600
electricity in an electrical circuit is
milliamperes?
Q = It. The correct expression for ‘t’ is
(A) 0.06A
(B) 0.6A
(A) Q/I
(C) 6A
(B) Q + t
(D) 60A
(C) QI
(D) Qi
27. The alloy known as constantan is
used in standard resistors because in case
21. Primary cells are those which
of a moderate rise in temperature it’s
(A) consist of two negative electrodes
resistance
(B) Can be recharged
(A) increases appreciably
(C) Carry an open circuit voltage of 1.5V
(B) Decreases appreciably
(D) Cannot be recharged
(C) Is hardly affected
(D) Fluctuates

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28. jelly
(D) Run cold water over the area
33. The resistance of a conductor is 0.05
ohms. What current is required to pass
through it to give a 6 Volt drop?

- - (A) 30A
-
-
(B) 40A
The two suspended-
electrical charges (C) 60A
illustrated above would (D) 120A
(A) attract each other
(B) repel each other 34. Electrical generating utilities in the
(C) rotate Caribbean distribute power at
(D) Vibrate frequencies of

29. The total resistance of two resistors (A) 30 or 40Hz

having the same value and connected in (B) 50 or 60Hz
parallel in a circuit would be (C) 70 or 80Hz
(A) three times the ohmic value of (D) 90 or 100Hz
one
(B) two times the ohmic value of one 35. An ‘electrical shock’ is a physical
(C) the same ohmic value of one sensation caused by the
(D) half the ohmic value of one
(A) amount of current that can result
30. Which of the following colour codes in serious damage to the muscles of a
shows the correct value for a resistor of persons body
1000 ohms? (B) changes in temperature of a
(A) Brown, black, red person’s body
(B) Brown Brown, red (C) Current passing through the
(C) Brown, brown, orange chest region of the body
(D) Brown, orange, brown (D) Reaction of the nerves to electric
current
31. Which of the following conditions would
present a low resistance path in an electrical 36. Which of the following are units of
circuit? energy?
(A) An open circuit I. Lumen
(B) A short circuit II. Joules
(C) A series circuit III. Kilowatt Hours
(D) A blown fuse
(A) I and II only
32. A person who gets an electrical burn (B) I and III only
should immediately (C) II and III only
(A) Apply mercurochrome ointment (D) I, II and III
to the area
(B) Apply gentian violet to the area
(C) Rub the area with petroleum

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(B) Ammeter in series with the load

(C) Voltmeter across the load
37. The colour bands on a resistor are (D) Ammeter across the load
red, orange, red. The coded value is
42. Which of the following colour codes
(A) 0.23kΩ shows the correct value for a resistor of
(B) 2.30kΩ 1000 ohms?
(C) 23.00kΩ
(D) 232kΩ (A) Brown, black, red
(B) Brown Brown, red
38. The frequency of an alternating (C) Brown, brown, orange
current source is the (D) Brown, orange, brown

(A) radian 43. The power dissipated by a 50Ω

(B) voltage variations in one resistor which is connected to a 24V d.c.
revolution supply is
(C) number of cycles in one second (A) 10.00w
(D) Completion of a set of specific (B) 11.52w
changes (C) 54.00w
(D) 360.00w
39. Which of the following solutions is
used as the electrolyte in a simple cell? 44. Which of the following should be
(A) Copper sulphate carried out last when treating an
(B) Zinc sulphate unconscious person who has had an
(C) Sulphuric acid electric shock?
(D) Ammonium chloride (A) Keeping airways to the lungs clear
(B) Loosening tight clothing
39. The collection of hydrogen bubbles (C) Administering artificial respiration
around the carbon electrode in a carbon- (D) Treating burns
zinc cell is called
(A) amalgamation 45. In which of the following graphs is
(B) local action ohm’s law verified?
(C) ionization
(D) polarization

40. What is the peak value of a 240V a.c.

supply?

(A) 152.8V
(B) 169.6V
(C) 339.4V
(D) 376.7V

41. To measure the voltage across a load,

one would connect a/an
(A) Voltmeter in series with the load

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46.
49. Which of the following circuits will
dissipate the most power?

47. Which of the following precautions

should be observed when checking the
resistance of an electrical circuit with an
ohmmeter?
(A) Adjust the meter of f.s.d. before
using
(B) Adjust the meter to its lowest scale
(C) Connect the meter to an a.c. source. 50. What effect does an ambient
(D) Ensure that no voltage is applied to temperature greater than 30oC have on
the circuit while resistance is being the current rating of a conductor?
measured.
(A) The current rating is decreased.
48. (B) The current rating is increased.
(C) The current rating remains

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unchanged.
(D) The current rating is multiplied by
the voltage drop

SECTION 2
Candidates MUST answer ALL SIX questions in this section.

1. The figure above indicates three resistance readings taken by an ohmmeter.

write the letters (X) , (Y) and (Z) . Next to EACH letter, write the value of reading
indicated. (6 marks – 2 marks each)
X - ______________ Y - _________________ Z – ______________

2. The figure below shows the dials of a five dial watt-hour meter for a JPS customer.
Calculate how much it would cost the customer for the one month period if he previous
reading was 1141 and the rate is $9.25/KWH. (3 marks)

________________________________________________________________________
________________________________________________________________________
________________________________________________________________________

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________________________________________________________________________

3. (a) State Ohm’s Law and write the formula that represents Ohms Law. (2 marks)
(b) Figure 1 shows a series parallel resistive circuit.

Figure 1
Calculate the
(i) Total resistance when the switch S is closed (1 mark)
(ii) Total resistance when the switch S is open (1 mark)
(iii) Total current I when the switch S is closed (1 mark)
(iv) Maximum power developed in the 9Ω resistor. (3 marks)
Total 8 marks

4. (a) State TWO (2) reasons why cells are connected in parallel. (2 marks)
(b) State TWO advantages of an alkaline cell over a lead-acid cell. (2 marks)
(c) A commercial battery, with an open circuit voltage of 14.4V, has a
terminal voltage of 12.2V when supplying a current of 20A to a load.
Calculate the internal resistance of the battery. (4 marks)
Total 8 marks

5. (a) Name THREE factors which affect the resistance of a metallic conductor.

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(4 marks)
(b) A copper cable 1500 m long, has a cross-sectional area of 25 x 10-6. The
resistivity of copper is 1.7 x 10-6 Ω m.
Calculate the resistance of the cable (4 marks)

(c) Describe the difference between positive and negative temperature

coefficients of materials. (2 marks

6. (A) Make a neat sketch of an a.c. sine wave. (4 Marks)

(B) Indicate the following values on the sketch in part (A) above:

(i) One cycle

(ii) Positive Peak Voltage
(iii) Peak to peak voltage
(iv) R.m.s. voltage (4
Marks)

(C) Name TWO electrical characteristics of an a.c. sine wave. (2 Marks)

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