HKCEE 1999 - 2003
PHYSICS - MC Questions
Electromagnetism
(1999-CE-PHY II - 26)
26.
An insulated metal sphere carries positive charges. Which of the following will
discharge the sphere ?
(1)
bringing an alpha source near the sphere
(2)
touching the sphere momentarily with a finger
(3)
bringing a negatively charged metal rod near the sphere (but without touching it)
A.
(1) only
B.
(3) only
C.
(1) and (2) only
D.
(2) and (3) only
E.
(1), (2) and (3)
(1999-CE-PHY II - 27)
27.
A student uses the above circuit to find the resistance of a resistor R (i.e.
. Which of the following statements is/are correct ?
(1)
The ammeter reading records the actual current passing through R.
(2)
The voltmeter reading records the actual potential difference across R.
(3)
The value of the resistance of R obtained is smaller than its actual value.
A.
(1) only
B.
(3) only
C.
(1) and (2) only
D.
(2) and (3) only
E.
(1), (2) and (3)
1
(1999-CE-PHY II - 28)
28.
In the above circuit, the current delivered by the cell is I. What is the current passing
through the 30 Ω resistor ?
A.
1
I
2
B.
1
I
3
C.
1
I
4
D.
1
I
5
E.
4
I
5
(1999-CE-PHY II - 29)
29.
A moving coil meter has a resistance of 10Ω. The above diagram shows how the meter
can be converted in to a 0-3 V voltmeter using position X and into a 0-15 V voltmeter
using position Y. Find the resistance of R.
A.
9 000Ω
B.
12 000Ω
C.
12 010Ω
D.
14 990Ω
E.
15 000Ω
2
(1999-CE-PHY II - 30)
30.
The above figure shows an incomplete circuit consisting of a battery, a resistor, two
identical bulbs and two diodes. If the negative terminal of the battery is connected to
points X, Y and Z in turn, find the number of bulbs that will light up in each case.
Connected to X Connected to Y Connected to Z
A.
0
1
1
B.
0
1
2
C.
0
2
2
D.
1
1
2
E.
1
2
1
(1999-CE-PHY II - 31)
31.
Two bulbs P and Q are connected to an ideal transformer as shown above . Which
of the following statements is/are true when switch S is closed ?
(1)
The brightness of bulb P decreases.
(2)
The reading of the ammeter increases.
(3)
The reading of the voltmeter remains unchanged.
A.
(1) only
B.
(3) only
C.
(1) and (2) only
D.
(2) and (3) only
E.
(1), (2) and (3)
3
(1999-CE-PHY II - 32
32.
The above diagram shows the trace of a signal on a CRO with the time base set at 10 ms
cm-1 and Y-gain at 1 V cm-1. If the time base is changed to 20 ms cm-1 and Y-gain
changed to 0.5 V cm-1, which of the following shows the trace of the signal on the
CRO ?
A.
B.
C.
D.
E.
(1999-CE-PHY II - 34)
34.
Which of the following is/are the advantage(s) of using high voltages for long distance
transmission of electricity ?
(1)
The transmission speed can be increased.
(2)
Some heavy industries operate at high voltages.
(3)
The energy loss in the transmission cable can be reduced.
A.
(1) only
B.
(3) only
C.
(1) and (2) only
D.
(2) and (3) only
E.
(1), (2) and (3)
4
(1999-CE-PHY II - 36)
36.
A ‘6 V, 6 W’ light bulb is to be operated at its rated value. Three circuits are set up as
shown below.
The power supplies all have negligible internal resistance. In which of the above circuits
is the bulb working at its rated value ?
A.
(1) only
B.
(3) only
C.
(1) and (2) only
D.
(2) and (3) only
E.
(1), (2) and (3)
(2000-CE-PHY II - 29)
29.
Two insulated uncharged metal spheres X and Y are placed in contact. A
positively-charged rod is brought near X as shown above. X is then earthed momentarily.
The charged rod is removed and the two spheres are then separated. Which of the
5
following describes the charges on X and Y ?
Sphere X
Sphere Y
A.
negative
negative
B.
negative
uncharged
C.
positive
positive
D.
uncharged
uncharged
E.
uncharged
positive
(2000-CE-PHY II - 30)
30.
Three resistors are connected to a battery as shown above. Which of the following
statements is/are correct ?
(1)
The current passing through R1 is equal to that passing through R2.
(2)
The potential difference across R1 is equal to that across R2.
(3)
The energy dissipated by a coulomb of charge passing through the
equal to that dissipated by a coulomb of charge passing through PQ.
A.
(1) only
B.
(3) only
C.
(1) and (2) only
D.
(2) and (3) only
E.
(1), (2) and (3)
6
4Ω-resistor is
(2000-CE-PHY II - 31)
31.
The switch S in the above circuit is closed, which of the following statements is/are
correct ?
(1)
The readings of ammeters A1 and A2 are both increased.
(2)
The ratio of the readings of ammeters A1 to A2 is increased.
(3)
The reading of ammeter A3 remains unchanged.
A.
(1) only
B.
(3) only
C.
(1) and (2) only
D.
(2) and (3) only
E.
(1), (2) and (3)
(2000-CE-PHY II - 32)
32.
In the above circuit, D1, D2 are diodes of negligible resistance and P, Q are identical
bulbs. Which of the bulbs will light up when
(1)
switch S is open, and
(2)
S is closed ?
7
S is open
S is closed
A.
P
Q
B.
Q
P and Q will not light up
C.
P and Q
P and Q
D.
P and Q
P and Q will not light up
E.
P and Q will not light up
P and Q
(2000-CE-PHY II - 33)
33. A moving coil milliammeter has a resistance of 10Ω and a full-scale deflection of
0.01A. It is converted into an ammeter with a full-scale deflection of 1.0A by connecting
a resistor R to it. Which of the following shows the resistance of R and the method of
connection ?
Resistance of R
Method of connecting R
and the milliammeter
A.
0.1Ω
in parallel
B.
0.1Ω
in series
C.
1Ω
in parallel
D.
90Ω
in parallel
E.
90Ω
in series
(2000-CE-PHY II - 34)
34.
A resistor and a bulb are connected in parallel to a 9 V battery as shown above. The
reading of the ammeter is 5 A. If the power dissipated by the resistor is 18 W, find the
power dissipated by the bulb.
A.
9W
B.
18 W
C.
22.5 W
8
D.
27 W
E.
45 W
(2000-CE-PHY II - 35)
35.
The above diagram shows the main parts of an electric iron. In which of the following
situations will the fuse blow when the switch is closed ?
(1)
The insulation at contact point
X is worn out so that the wire touches the metal
case.
(2)
The insulation at contact point Y is worn out so that the wire touches the metal
case.
(3)
The heating element is broken.
A.
(1) only
B.
(3) only
C.
(1) and (2) only
D.
(2) and (3) only
E.
(1), (2) and (3)
(2000-CE-PHY II - 36)
36.
9
The above diagram shows an experimental set-up for measuring the resistance of a bulb.
To which of the terminals P, Q and R of the ammeter and voltmeter should each of the
wires be connected ?
Wire (1)
Wire (2)
Wire (3)
A.
P
Q
R
B.
P
R
Q
C.
Q
P
R
D.
R
P
Q
E.
R
Q
P
E.
Switch S is open and the temperature of X is low.
(2000-CE-PHY II - 38)
38. A bar magnet is placed near a solenoid. Which of the following correctly shows the
direction of the induced current in the solenoid ?
(Note : The arrow”
“ indicates the direction of motion of the magnet or solenoid.)
A.
B.
C.
D.
E.
10
(2000-CE-PHY II - 40)
40. Which of the following statements aboutαparticles andγrays is correct ?
A.
Both of them carry charges.
B.
Both of them are transverse waves.
C.
Both of them can be deflected by a magnetic field.
D.
Both of them have strong ionizing power.
E.
Both of them can travel through a vacuum.
(2001-CE-PHY II - 27)
27. Which of the following relations is incorrect ?
A.
1 pascal (Pa)
=
1 newton per metre squared (N m-2)
B.
1 watt (W)
=
1 joule per second (J s-1)
C.
1 coulomb (C) =
1 ampere per second (A s-1)
D.
1 volt (V)
=
1 joule per coulomb (J C-1)
E.
1 ohm (Ω)
=
1 volt per ampere (V A-1)
(2001-CE-PHY II - 28)
28.
Two charged spheres A and B are hanging at a point on a ceiling by two identical nylon
threads. They remain at rest as shown above. Which of the following statements must be
correct ?
(1)
Both spheres carry positive charges.
(2)
The force acting on B by A is larger than the force acting on A by B.
(3)
The mass of A is larger than B.
A.
(1) only
B.
(3) only
C.
(1) and (2) only
D.
(2) and (3) only
E.
(1), (2) and (3)
11
(2001-CE-PHY II - 29)
29.
If the ammeter in the above circuit reads 3 A, find the voltage of the battery.
A.
11 V
B.
12 V
C.
13.5 V
D.
15 V
E.
18 V
(2001-CE-PHY II - 30)
30.
In the above circuit, the two resistors are identical. If switch S is closed, which of the
following predictions is incorrect ?
A.
The reading of the ammeter A1 increases.
B.
The reading of the ammeter A2 remains unchanged.
C.
The reading of the voltmeter remains unchanged.
D.
The power delivered by the battery increases.
E.
The potential difference between points X and Y increases.
12
(2001-CE-PHY II - 31)
31. Which of the following diagrams shows the correct connection of the fuse and switch of
an electric kettle to the mains supply ?
(L : live, N : neutral, E : earth)
A.
C.
E.
(2001-CE-PHY II - 32)
32. Two electrical heaters X and Y are of ratings ‘110 V, 40 W’ and ‘110V, 80 W’
respectively. Which of the following deductions about the two heaters is/are correct ?
(1)
The operating resistance of X is twice that of Y.
(2)
X will consume a power of 80 W when it is connected to a 220 V mains supply.
(3)
Both heaters work at their rated values when they are connected in series to a 220
V mains supply.
A.
(1) only
B.
(3) only
C.
(1) and (2) only
D.
(2) and (3) only
E.
(1), (2) and (3)
13
(2001-CE-PHY II - 33)
33.
Figure (a)
Figure (b)
Figure (a) shows the trace of a signal on a CRO. In order to change the trace of the
signal into the form shown in Figure (b), which of the following settings of the CRO
should be adjusted ?
A.
Y-gain only
B.
Y-shift only
C.
time base only
D.
Y-gain and Y-shift
E.
Y-gain and time base
(2001-CE-PHY II - 34)
34.
A 12 V a.c. supply is connected to a transformer with turns ratio 1 : 1. The secondary
coil is tapped at equal intervals as shown above. Two ‘6 V, 0.5 W’ light bulbs are
connected to the secondary coil of the transformer. In which of the following cases will
the two bulbs work at their rated values ?
(1)
(2)
14
(3)
A.
(1) only
B.
(3) only
C.
(1) and (2) only
D.
(2) and (3) only
E.
(1), (2) and (3)
(2001-CE-PHY II - 35)
35.
A long solenoid is placed in a vertical position and its two ends are
connected to the
Y-input of a CRO (with the time base switched on). A bar magnet is released above the
solenoid so that it falls through the solenoid. Which of the following best represents the
trace shown on the CRO ?
15
A.
B.
C.
D.
E.
(2001-CE-PHY II - 36)
36.
The figure above shows an electromagnet which is used to pick up iron objects. Which
of the following can increase the strength of the electromagnet ?
(1)
increasing the number of turns of the coil
(2)
reducing the resistance of the variable resistor
(3)
replacing the battery with a 12 V a.c. power supply
A.
(1) only
B.
(3) only
C.
(1) and (2) only
D.
(2) and (3) only
E.
(1), (2) and (3)
16
(2002-CE-PHY II - 30)
30.
In the above circuit, both ammeters A1 and A2 read
1 A when switch S is open. Find the
readings of the two ammeters when S is closed.
A1
A2
A.
0.5 A
1.5 A
B.
0.67 A
1A
C.
1A
1.5 A
D.
1A
3A
(2002-CE-PHY II - 31)
31.
A plastic ruler is placed close to a stream of running water coming from an insulated tap.
The stream of water is attracted towards the ruler as shown above. Which of the following
statements are correct?
(1)
The ruler carries an electric charge.
(2) The ruler and the running water are attracting each other with forces of equal
magnitude.
(3) Both positive and negative charges are induced on the running water.
A. (1) and (2) only
B. (1) and (3) only
C. (2) and (3) only
17
D. (1), (2) and (3)
(2002-CE-PHY II - 32)
32.
P, Q and R are three parallel straight wires carrying equal currents flowing out of the
paper. R is equidistant from P and Q. What is the direction of the resultant force acting on
R by P and Q ?
A. 
B. 
C. 
D. 
(2002-CE-PHY II - 33)
33.
The figure above shows the voltage-current ( V-I ) graphs of two resistors X and Y. Which
of the following deductions is/are correct ?
(1)
The resistance of X is higher than that of Y.
(2) If X and Y are connected in series, the V-I graph of the combined resistor will lie in
region P.
(3) If X and Y are connected in parallel, the V-I graph of the combined resistor will lie in
region Q.
A. (2) only
B. (3) only
C. (1) and (2) only
D. (1) and (3) only
18
(2002-CE-PHY II - 34)
34.
Three identical lamps L1, L2 and L3 of ratings ‘6 V, 12 W’ are connected to a 6 V battery as
shown above. Which of the following statements is correct?
A. The potential difference across L2 is 3 V.
B. The current passing through L1 is 2 A.
C. The total power drawn from the battery is 12 W.
D. The total power dissipated in L1 and L2 is smaller than that in L3.
(2002-CE-PHY II - 36)
36.
If the live and neutral wires of an electric kettle are mistakenly interchanged inside the
plug as shown above, which of the following will happen ?
A. The kettle will not operate.
B. The fuse of the kettle will blow.
C. The metal case of the kettle will still stand at a high potential even when the
switch of the kettle is off.
D. The heating element of the kettle will still stand at a high potential even when the
switch of the kettle is off.
(2002-CE-PHY II - 37)
37. Which of the following shows how a moving-coil galvanometer can be converted into a
voltmeter ?
19
(2002-CE-PHY II - 38)
38.
The figure above shows a model power line. An a.c. supply and two ideal transformers
are used to operate a lamp of rating ‘6 V, 24 W’. The total resistance of the cables AB and
CD is 10  . If the lamp operates at its rated value, find the power loss in the cables.
A. 0.4 W
B. 3.6 W
C. 160 W
D. 1440 W
(2003-CE-PHY II - 31)
Four point charges of equal magnitude are placed at the four vertices of a square. The signs of
the charges are as shown above. A point charge C is placed at the centre of a square. What
will be the direction of the resultant electrostatic force, if any, acting on C?
A.
→
20
B.
↑
C.
The resultant force acting on C is zero.
D.
It cannot be determined since the sign of C is not given.
32 (2003-CE-PHY II - 32)
A square loop PQRS is made of uniform resistance wire. Let X, Y and Z be the equivalent
resistance of the loop when connected as shown below:
Which of the following relations is correct?
A.
X =Y =Z
B.
X =Z >Y
C.
X =Z <Y
D.
X <Y <Z
33 (2003-CE-PHY II – 33)
Figure (a) shows a circuit used to investigate how the potential difference V across a
resistance wire varies with the current I through the wire. The result is shown in Figure
(b). If the experiment is repeated using a thinner wire of the same material and of equal
21
length, which of the following graphs (denoted by the dashed line) represents the
expected result?
34 (2003-CE-PHY II - 34)
Three light bulbs P, Q and R of ratings ‘24 V,
80 W’, ‘12 V, 80 W’ and ‘12 V, 40 W’ respectively are connected in parallel to a 12 V
battery. Which of the bulbs will be the brightest, and which will be the dimmest?
The brightest
The dimmest
A.
P
Q
B.
P
R
C.
Q
P
D.
Q
R
22
35 (2003-CE-PHY II - 35)
The photograph shows a three-pin plug of an appliance. Which of the following is a
function of pin P?
A.
It prevents the appliance from being short-circuited.
B.
It protects the user from getting an electric shock.
C.
It provides a return path for the current.
D.
It can break the circuit when the current flowing through the appliance is too large.
36 (2003-CE-PHY II - 36)
The figure shows the energy label of a washing machine. If the average working time per
wash is 1.8 hours, estimate the average electric power consumed by the machine.
A.
450 W
B.
534 W
23
C.
962 W
D.
1731 W
37 (2003-CE-PHY II - 37)
Two compasses P and Q are placed near the poles of an electromagnet as shown above.
In which of the following diagrams are the north poles of the compass needles pointing
in the correct directions?
P
Q
A.
B.
C.
D.
24
38 (2003-CE-PHY II – 38)
Two coils P and Q are wound on a soft-iron core as shown above. Switch S is closed and
then opened again. Which of the following shows the directions of the induced current
flowing through the resistor R?
25