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ELECTRIC CURRENT
TEST REVIEW
A. Series
C. Both
1.
2.
3.
4.
5.
6.
7.
8.
9.
B. Parallel
D. Neither
C Potential difference and current are directly related.
A A(n) _____ circuit has only one path.
B A(n) _____ circuit has multiple paths.
B The resistance decreases as more resistors are
added.
B The potential difference is the same through all
resistors.
A The potential difference through all the resistors
adds up to the total.
D Current will flow if the circuit is open at the charge
pump (battery).
A The current is the same through all resistors.
C Potential difference is supplied by the charge pump
(generator).
A. Series
C. Both
B. Parallel
D. Neither
10. B When one light goes out, the rest stay on in a _____
circuit.
11. A When one light goes out, so do the rest in a ____ circuit.
12. C Current and resistance are inversely related.
13. A The individual resistors add up to the total resistance.
14. D Light bulbs supply current.
15. B The current through all the resistors adds up to the total.
16. B The voltage drop is the same through all branches of the
circuit.
17. B The individual resistors are all larger than the total
resistance.
18. B The total (equivalent) resistance is smaller than the
resistance of any of the resistors.
19.
Symbol
(Variable)
Measurement:
Unit Name:
Unit
symbol
I
Potential
Difference
(voltage)
Current
R
Resistance
ohms
Ω
P
Power
watts
W
V
Volts
V
Amps
A
20. Which has less resistance? A cold, thick,
short wire or a hot, thin, long wire?
cold, thick, short wire
21. The rate at which energy is used up by a
circuit is called ____.
Power
22. The rate at which charge flows through a
circuit is called __.
Current
23. Identify each statement as True or False:
a. F flow of charge is faster than the conventional current.
b. T A resistors resistance CANNOT be changed by
c.
d.
e.
f.
g.
h.
increasing or decreasing the current.
F Electron flow is in the SAME direction as conventional
current.
T The voltage supplied by a battery does NOT change
as the current increases or decreases.
T Resistance slows down the current in a circuit.
F A 60 W light bulb uses up more energy and draws a
greater current than a 100 W light bulb.
T Voltage describes the potential difference in a circuit.
T A household wall outlet contains 120V.
24. Identify each statement as AC (alternating
current) or DC (direct current).
a) AC Electrons move back and forth.
b) DC Flow of charge is always in one
c)
d)
e)
f)
direction.
DC Used in a flashlight
DC Used in a car
AC Used in a bathroom light
DC As electrons move through a resistor,
their voltage drops.
25. Which Diagram shows the correct
placement of an ammeter and a voltmeter?
ANSWER: D
26. Identify the following Symbols:
Light bulb
Switch
Resistor
Voltmeter
Battery
(Charge Pump
Ammeter
27. A gasoline generator converts chemical energy to
potential energy.
28. A wind turbine converts kinetic energy to potential
energy.
29. A battery converts chemical energy to potential
energy.
30. What do you need to form a circuit?
battery (charge pump), wires or conductors, and
light bulb or other resistor.
31. Calculate the total resistance if you have
three resistors in a series circuit that are: 4Ω, 5
Ω, and 7 Ω.
4 + 5 + 7 = 16 ohms
32. Calculate the total resistance in a parallel
circuit if there are three resistors that are: 4 Ω, 4
Ω, and 6 Ω.
1/4 + 1/4 + 1/6 = 1.5 ohms
USE: V = I●R or P = V●I
33. If a 15 V battery is connected to a light bulb with 5 A of
current, what is the resistors value?
R = V/I = 15/5
R = 3 ohms
34. What is the potential difference supplied by an appliance that
has a resistance of 40 ohms and draws 3 Amps of current?
V = IR
V = 3 x 40 = 120V
35. A 60 ohm resistor is plugged into a wall outlet, how much
current flows through the resistor? (hint – you need to know the
voltage in a wall outlet)
I = V/R = 120/60
I = 2A
USE: V = I●R or P = V●I
36. What is the voltage supplied by a resistor using 12 Watts that draws
4 A of current?
P = VI
V = P/I = 12/4 = 3V
37. A 45 Watt light bulb is connected to a wall outlet. How
much current exists in the light bulb?
(hint: you should know the voltage in a wall outlet).
P = VI
I = P/V = 45/120 = 0.4A
38. A current of 4.5 amps flows through a light bulb and is connected to
a 6 volt battery. What much power is the bulb using?
P = VI
6 x 4.5 = 27 W
39. Complete the Chart
R1
R2
R3
V
100 V
I
R
P
Total
12 Ω 33 Ω 22 Ω
40. Complete the Chart:
R1
100
Ω
R2
300
Ω
R3
50
Ω
R1
R2
R3
V
12 V
I
R
P
Total
100 Ω
300 Ω
50 Ω
41. Identify the following statements as GFCI
Outlet, Fuse, or Circuit Breaker:
a. GFCI Outlet Protects someone from
being electrocuted if they fall into a bath
tub with a hair dryer.
b. Fuse Found in cars
c. Circuit Breaker Found in houses to turn
off a circuit if too much current flows.
d. GFCI Outlet Found anywhere there is
water present.
42. The cost of electricity is $0.09 per kW-h. If a 0.8 kW
refrigerator runs for 8 hours, how much will it cost?
.8kW x 8 hours = 6.4kW-h x .09
0.58 cents
43. If an appliance uses 500 watts of power, how much
energy is used up (kW-h) if it is left on for 3hours? (hint –
convert watts to kW first).
500/1000 = .5kW x 3 hours = 1.5kW-h
44. If an appliance runs for 5 minutes (300 seconds) and
uses 125,000 J of energy, what is the power rating of the
appliance? Use the equation:
125000 J
P
300 s
P = 416.7 W