Let's Review
Section A: Multiple-Choice Questions
Section B: Short Structured Questions
1
4
In the circuit diagram below, 10 units of electric
charge move past point X every second.
Look at the scene below. Can you spot the ways
in which energy is being wasted? Write down
what you would do instead to conserve energy
at home.
X
What is the current in the circuit?
A
10 A
B
1A
C
10 V
D
1V
2
Four identical light bulbs are connected
as shown in the diagram below. Predict
which light bulbs will continue to light up
when a wire of ver y low resistance is joined
between points X and Y. (Hint: The larger the
resistance of the wire, the lower the current
flowing in the wire.)
▲ Figure 13.37 Wastage of electrical energy at home
5
Two electric circuits are shown in the diagrams
below. One of the wires (marked on the
diagrams with a red cross) is broken. Predict
what would happen to the brightness of the
bulbs. Explain your answers.
Q
X
▲ Figure 13.38 Two light bulbs connected in
parallel and in series
Y
P
6
In a recycling project, Isaac collects a mixture
of different light bulbs. He tests the bulbs by
passing the same current through each bulb.
Some of the bulbs are brighter than the others,
and some bulbs do not light up. He decides to
conduct an experiment to find out what factors
determine the brightness of a light bulb.
(a) What questions should Isaac ask before
conducting his experiment?
(b) What hypothesis should Isaac formulate
for his experiment?
7
Optional for N(A)
A television is rated 150 W and a refrigerator
is rated 1 kW. The total electrical energy used
by these appliances by a family in a week is
11.5 kWh.
(a) Suppose both the television and
refrigerator were switched on for the
same amount of time throughout the
week. For how many hours was each of
the appliances switched on during the
entire week?
(b) The refrigerator was replaced with
another refrigerator rated 1,200 W.
How much more does the family pay for
electrical energy each week? (Assume
electricity costs 30 cents per kWh.)
S
R
A
C
3
P and S only
All the bulbs
B
D
Q and R only
None of the bulbs
A circuit is being set up in an experiment
to measure the resistance of a coil of wire
(C). Which circuit below is suitable for this
experiment?
A
B
C
A
C
A
V
C
D
C
V
84
V
V
C
A
A
Chapter 13
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9/20/12 11:21 AM