Download Practice Test-CP- Electricity 2010

Name: __________________________
Test on Electricity 2013 v. A
Period _____
Burns
(70 points)
Date: ________
Honors Physics
Problem #1 (20 points)
Station # _______
There is a real circuit with 3 resistors in either series or in parallel with a power supply. DO NOT TOUCH
THE DIAL ON THE POWER SUPPLY. You should only switch it “ON” when you are ready to take your
measurements and turn it “OFF” when you are done.
1. Draw the schematic of the set up. (4)
Measured
2. You will use your multimeter from last week. If you blew a fuse and put the meter
away like that, you will lose the point for this part. Use the multimeter ONLY to
measure the current and the voltage in the marked resistor. Record it in the box
to the right. You may NOT make any other measurements. (2)
∆VR1 = _______
I 1 = _________
3. Go back to #1 and draw in the symbols for the ammeter and voltmeter. Place them in the correct
locations so that they will measure current and voltage in R1. (2)
4. Record the colors of the bands on all 3 resistors. Then return to your seat. Decode the resistor
using the chart to the right. (3)
Resistor
1
1st Band
2nd Band
3rd Band
4th Band
Gold
2
Gold
3
Gold
Decoded R
5. Complete the rest of the circuit analysis to find the information listed below. (9)
R2 = ________
R3 = ________
Req = ________
∆VR2 = _______
∆VR3 = _______
∆Vbattery = _______
I 2 = _______
I 3 = _______
I battery = _______
Problem #2 (17 points)
a) Find the missing information. (12)
R1 = ________
∆VR1 = 20V
I 1 = _________
Req = _________
∆Vbattery = 30 V
Ibattery = ________
R3 = ________
∆VR3 = _______
I 3 = 0.5A
R2 = ________
∆VR2 = _______
I 2 = 0.5A
R4 = _______
∆VR4= ________
I 4 = 0.4A
R5 = _________
∆VR5 = 4V
I 5 = ________
b) Write out the loop rule for each loop. (3)
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c) Write out the junction rule for each junction. (2)
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Problem #3 (18 points)
a) Briefly explain the role of a fuse OR circuit breaker and how it works. (4)
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You are provided with the following appliances that are commonly found in a teenage bedroom. The bedroom has one 15A circuit and operates on 120 volts.
Hair dryer (10A)
Desk lamp (60W)
Laptop (50W)
Xbox (100 W)
Ceiling light with (4) 13-W-bulbs
Clock (15W)
Curling Iron (800W)
TV (200 W)
Phone charger (290 mA)
Fan (230W)
Radio (70W)
Space heater (1000W)
Printer (65W)
Night light (5W)
Stereo (750 mA)
b) Make a (sensible) list of appliances that will use the maximum amount of energy without blowing
a circuit breaker (fuse). Back up your answer with calculations. (5)
c) Draw a schematic diagram of your bedroom circuit with the logical placement of switches and
fuses. (5)
d) Power is the energy used per second, and has units of [J/s]. The equation E = P*t tells how much
energy some device uses when running for a time t. Using this new definition of Power, estimate
how much energy you need to run just your Clock in a typical week. (4)
Multiple Choice: Identify the choice that best completes the statement or answers the question. Fill in the
corresponding oval on your Scantron sheet. (1 point each = 15)
1) If the voltage across an ohmic resistor is reduced by a factor of 2 (halved), what happens to the
current through it?
a) It doubles.
b) It quadruples.
c) It halves
d) It is quartered.
e) It depends on the resistance.
2) Assuming that, in the diagrams below, all light bulbs are identical in resistance and design, and that all
batteries are identical in voltage, which of the scenarios below has the brightest bulb(s)?
b)
a)
d)
c)
3) Use the chart to the right to answer the following question. What is the resistance of a
coded resistor with the bands: red - green - orange.
a) 250 Ω
b) 2500 Ω
c) 253 Ω
d) 25000 Ω
4) When one bulb is unscrewed from the middle socket, but nothing else is changed,
what happens to the remaining bulbs in the circuit shown below?
a)
b)
c)
d)
The remaining bulbs are brighter.
The top bulb lights, but the bottom one goes out.
The remaining bulbs go out.
The remaining bulbs are dimmer, but remain lit.
5) Two lamps, one with a thick filament and one with a thin filament, are connected in series to a battery.
The voltage is greater across the lamp with the
a) thin filament.
b) thick filament.
c) Voltage is the same for both.
6) Where do the electrons come from that produce heat and light in a light bulb?
a) the power company
b) the air
c) the wall plug
d) the battery
e) none of the above
7) Four identical light bulbs K, L, M, and N are connected in the electrical circuit
shown to the right. In order of decreasing brightness (starting with the brightest), the bulbs are:
a) K = L > M > N
b) K = L = M > N
c) K > L = M > N
d) N > K > L = M
e) N > K = L = M
8) Which sentence best describes electrical insulators?
a) Electrical insulators have electric charges that do not move freely.
b) Electrical insulators have electric charges that do not move at all.
c) Electrical insulators have electric charges that move freely.
d) Electrical insulators are good heat conductors.
9) Which of the following wires would have the greatest resistance?
a) an aluminum wire 10 cm in length and 3 cm in diameter
b) an aluminum wire 5 cm in length and 3 cm in diameter
c) an aluminum wire 10 cm in length and 5 cm in diameter
d) an aluminum wire 5 cm in length and 5 cm in diameter
10)The power ratings on light bulbs are measures of the
a) rate at which they give off heat and light.
b) voltage they require.
c) density of the charge carriers.
d) amount of negative charge passing through them.
11)In a circuit with a single light bulb, are charges being converted to light?
a) Yes, charges moving through the filament produce "friction" which heats up the filament and
produces light.
b) Yes, charges are emitted by the bulb in the form of light.
c) No, charge is conserved. It is simply converted to another form such as heat and light.
d) No, charge is conserved. Charges moving through the filament produce "friction" which heats up
the filament and produces light.
12)How does the power delivered to resistor A change when resistor B is added as shown in circuits 1
and 2 respectively?
a) Increases
b) Stays the same
c) Decreases
d) No way to tell without knowing the resistance of A and B.
13)Compare the current at point 1 with the current at point 2. Which point has the larger current?
a) Point 1
b) they are the same
c) point 2
d) can’t tell from the information
14)Consider the power delivered to each of the resistors shown in the circuits below. Which circuit or
circuits have the least power delivered to it?
a)
b)
c)
d)
e)
Circuit 1
Circuit 2
Circuit 3
Circuit 1 = Circuit 2
Circuit 2 = Circuit 3
15)If you double the current through a battery, is the potential difference across a battery doubled?
a) Yes, because Ohm's law says V = IR .
b) Yes, because as you increase the resistance, you increase the potential difference.
c) No, because as you double the current, you reduce the potential difference by half.
d) No, because the potential difference is a property of the battery.
e) No, because the potential difference is a property of everything in the circuit