Download 9 electricity test - circuits

Grade 9 Science
Electricity Test – Circuits and Ohm’s Law
1) Below is a typical electric circuit. Label the parts of the circuit.
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2) Below are four circuits. Label each one as series or parallel or both.
a)
b)
c)
d)
3) Below is a circuit with four bulbs in it.
a) Place four switches in the circuit so each switch only controls one light bulb. Label each
switch with the letter of the bulb it controls.
b) Insert a switch that will turn off only three bulbs. Label it E
c) Insert a switch that will turn off all the bulbs. Label it F
4) Draw a parallel circuit with three light bulbs in series along with a loudspeaker. Include a
switch.
5) Draw a typical circuit you would use to test the resistance of a resistor. Make sure you
include a voltmeter and an ammeter.
6) If the voltage source (battery) in a circuit was 10 V and a 6 V battery was added in series,
what would the voltage of the circuit be?
7) Christmas tree lights can be bought in either series or parallel circuits. Choose which
type would be the better purchase. Explain why you think you chose the better one.
8) The lights in your home should be wired in parallel.
a) Why is that?
b) Explain what would happen if the light sockets were in series instead of in parallel.
9) Below is a graph comparing two resistors, A and B.
Resistance of Two Loads
90
80
70
Load A
Voltage
(V)
60
50
Load B
40
30
20
10
0
0
2
4
6
8
10
12
14
16
18
Current (A)
a)
Which load has a higher resistance?
______________
b)
Find the voltage if 8 A is applied to Load B.
______________
c)
Find the current if 35 V is applied to Load A.
______________
d)
What is the resistance of Load A?
______________
10) A voltmeter is always hooked up in ______________ but an ammeter is always hooked up
in ________________.
11) Fill in the triangle for Ohm’s law:
12) A circuit has a resistor in it that has a resistance of 10  and the ammeter hooked up in
the circuit shows 2.5 amps. What is the voltage in the circuit? Show your work!
13) A student hooks up a voltmeter and an ammeter in a circuit to find the resistance of a
light bulb. The ammeter read 0.2 amps and the voltmeter reads 4.5 volts. What is the
resistance of the light bulb?
14) Three 1.5 volt batteries are connected in series in a circuit with a loudspeaker that has an
8  resistance. What will an ammeter read if it is also connected into the circuit?
15) A circuit was set up to find out the resistance of a motor in an electric car.
a) On the sheet of graph paper provided, graph the following data on a current – voltage
graph. Label both axis.
Current (A)
0
2
4
6
8
10
12
14
16
18
Voltage (V)
0
6
16
19
30
35
40
50
56
65
b) Draw a line of best fit on your graph.
c) Calculate the slope of your graph. Show your calculations in the space below.
d) What is the resistance of the motor in the electric car?
e) Explain why the slope of a line on a current – voltage graph is the same as the resistance.