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WorksheetsCurrents Circuits
Total questions: 15
Worksheet time: 27mins
If a quantity you calculated has units of A • s, what is that quantity?
potential
resistivity
resistance
charge
For the graph shown in the figure, what physical quantity does the slope of the graph represent for ohmic material?
power
resistivity
resistance
1/(resistance)
The length of a certain wire is kept same while its radius is doubled. What is the new resistance of this wire?
It is increased by a factor of 2.
It is increased by a factor of 4.
It is reduced by a factor of 2.
It is reduced by a factor of 4.
The length of a certain wire is doubled while its radius is kept constant. What is the new resistance of this wire?
It is 2 times as large.
It is 3 times as large.
It is 4 times as large.
It is 1/2 as large.
Consider two copper wires of equal cross-sectional area. One wire has 3 times the length of the other. How do the resistivities of these two wires compare?
Both wires have the same resistivity.
The longer wire has 3 times the resistivity of the shorter wire.
The longer wire has 9 times times the resistivity of the shorter wire.
The longer wire has 27 times times the resistivity of the shorter wire.
When the current through a resistor is increased by a factor of 4, the power dissipated by the resistor
decreases by a factor of 4.
decreases by a factor of 16.
increases by a factor of 16.
increases by a factor of 2.
Over ordinary temperature ranges, the resistance of most metals such as copper
is independent of the temperature of the metal.
decreases as the metal gets hotter.
increases as the metal gets hotter.
is a maximum at 20°C.
If a charge of 12 C passes through a computer in 2 min, what is the average current through the computer?
24 A
6 A
0.1 A
10 A
A current of 1.6 A flows through an electrical device for 10 seconds. How many electrons flow through this device during this time? (e = 1.60 × 10-19 C)
1
16
1.0×1020
1.0×1019
What potential difference is required across an 8.0-Ω resistor to cause 2.0 A to flow through it?
4.0 V
16 V
32 V
128 V
The current through a piece of lab equipment must be limited to 3.0 A when it is run by a 120-V dc power supply. What must be the resistance of this equipment?
4 Ω
40 Ω
360 Ω
0.025 Ω
A 4000-Ω resistor is connected across a 200-V power source. What current will flow through the resistor?
0.1 A
8 A
0.05 A
20 A
A 20-m wire of 0.10 mm2 cross-sectional area draws 0.5 A when connected across a 3.0-V potential difference.
(a) What is the resistance of the wire?
(b) What is the resistivity of the material from which the wire is made?
(a) 1.5 Ω (b) 6.0 × 10-9 Ω • m
(a) 1.5 Ω (b) 3.0 × 10-8 Ω • m
(a) 6.0 Ω (b) 3.0 × 10-8 Ω • m
(a) 6.0 Ω (b) 6.0 × 10-9 Ω • m
The power rating of a 4000-Ω resistor is 0.400 W.
(a) What is the maximum safe voltage across this resistor?
(b) What is the maximum current the resistor can safely draw?
(a) 40 V (b) 0.01 A
(a) 0.01 V (b) 40 A
(a) 40 V (b) 100 A
(a) 100 V (b) 40 A
An instrument is rated at 220 W if it is connected across a 110-V dc power supply.
(a) What current does it draw under normal operation?
(b) What is its resistance?
(c) How many kilowatt-hours does it use in a day if it is left on for 10 hours?
(a) 2.0 A (b) 55 Ω (c) 22 kWh
(a) 2.0 A (b) 55 Ω (c) 7920 kWh
(a) 55 A (b) 2.0 Ω (c) 2.2 kWh
(a) 2.0 A (b) 55 Ω (c) 2.2 kWh
