Unit 7 Test
Three resistors, which measure 45Ω, 10Ω, and 30Ω are connected in series to a 24 V battery. The Req is 85Ω. The total current is 0.282 A. Find the voltage across each resistor.
12.69 V, 2.82 V, 8.46 V
What is the unit of resistance?
Ohms or V/A
Three identical resistors are wired in parallel with a battery. Each resistor has resistance R. Write an expression to find the Req of the circuit?
R/3
T/F: You have one light bulb connected to a battery so that the bulb is lit. If you add a second bulb to the circuit, in parallel, the voltage across the first bulb decreases.
false
T/F: You have one light bulb connected to a battery so that the bulb is lit. If you add a second bulb to the circuit, in parallel, the first bulb gets dimmer.
false
T/F: You have one light bulb connected to a battery so that the bulb is lit. If you add a second bulb to the circuit, in series, the first bulb gets dimmer.
true
T/F: You have one light bulb connected to a battery so that the bulb is lit. If you add a second bulb to the circuit, in series, the voltage across the first bulb decreases.
true
T/F: Current is defined as the rate of flow of energy in a circuit
false
T/F: Home electrical wiring is done in parallel so that each device receives the same current
false
T/F: In a parallel connection, the largest resistor will have the largest current
false
T/F: In regards to a series circuit, adding more light bulbs will not affect the brightness of the bulbs.
false
T/F: In regards to a series circuit, as more light bulbs are added, the total current increases
false
T/F: In regards to a series circuit, each bulb receives a different amount of current.
false
T/F: In regards to a series circuit, if one bulb is removed, the others will remain lit.
false
T/F: In regards to resistors wired in parallel, as more resistors are added, the current through the battery decreases
false
T/F: In regards to resistors wired in parallel, each resistor has a direct "line" to the battery, so they all receive the same current
false
T/F: In regards to resistors wired in parallel, the Req increases as more resistance is added
false
T/F: In regards to resistors wired in parallel, the smallest resistor will have the smallest current running through it
false
T/F: The conventional current is the current that always exits from the negative terminal of the battery
false
T/F: The total resistance in a parallel circuit increases as more resistors are added
false
T/F: The total resistance in a series circuit decreases as more resistors are added
false
T/F: The voltage is the same for all resistors that are connected in series
false
A lamp is left on for 24 hours a day. How much does she pay for electricity each month to light the 60W bulb? The company charges $0.08/kWh.
$3.46
Three resistors are connected in parallel. The resistors have a resistance of 1Ω, 2Ω, and 3Ω. The battery has a current of 765 mA. Find the current in the 2Ω resistor.
0.209 A
Three resistors, which measure 45Ω, 10Ω, and 30Ω are connected in series to a 24 V battery. The Req is 85Ω. Find the total current that travels through the circuit.
0.282 A
Suppose you always forget to turn off one of the 75W light bulbs in your kitchen. You leave it on for 24 hours a day. How much electrical energy do you use in a day to keep that bulb lit?
1.8 kWh
If a source has a current of 2.4A, how many Coulombs of charge pass through the source every second?
2.4 C
You have a 9V battery connected to two resistors in parallel with resistances of 6Ω and 3Ω. Find the total current.
4.5 A
A 3Ω resistor is connected to a 6V battery. An unknown resistor is added to the circuit in parallel. The total current with both resistors is 3.2A. What is the resistance of the unknown resistor?
5 Ohms
Suppose you have three resistors: 15Ω, 25Ω, and 30Ω. You can wire the resistors in series or in parallel. What do you get when they are in series?
70Ω
Suppose you have three resistors: 15Ω, 25Ω, and 30Ω. You can wire the resistors in series or in parallel. What do you get when they are in parallel?
7Ω
Three resistors, which measure 45Ω, 10Ω, and 30Ω are connected in series to a 24 V battery. Find the Req.
85 Ohms
You have a 9V battery connected to two resistors in parallel with resistances of 1Ω and 2Ω. The source current is 13.5A. Find the current through each resistor.
9 A, 4.5 A
Consider a circuit that contains three identical resistors. "If I arrange the three resistors in series, then each resistor gets the same amount of current. If i arrange them in parallel, they each get the same amount of current. Therefore, the total current in both circuits must be the same." Which parts of this statement are correct?
All resistors in series get the same amount of current. Identical resistors get the same amount of current in parallel.
Name the 3 units of power.
Hp, J/s, W
Suppose you have a battery connected to 7 identical resistors in parallel. Each resistor has resistance R. The source current is I. Write an expression to find the current through each resistor.
I/7
Consider a circuit that contains three identical resistors. "If I arrange the three resistors in series, then each resistor gets the same amount of current. If i arrange them in parallel, they each get the same amount of current. Therefore, the total current in both circuits must be the same." Which parts of this statement are incorrect?
Req is different in series and parallel circuits, therefore the total current in both circuits isn't the same.
Three resistors measure 45Ω, 10Ω, and 30Ω. Which resistor will dissipate the least amount of power?
Resistor 2
A kilowatt-hours measures...
energy
Consider a circuit that contains three identical resistors. How do you rearrange the circuit to make sure each resistor gets the maximum possible voltage?
parallel
Series, parallel, or both? The Req is always less than any resistor in the circuit
parallel
Series, parallel, or both? The largest resistor will use the least amount of power
parallel
You have three identical resistors. How do you wire the circuit to get the greatest possible current?
parallel
Series, parallel, or both? Current through the battery increases as more resistors are added
parellel
Series, parallel, or both? Current through the battery decreases as more resistors are added
series
Series, parallel, or both? Equivalent resistance is always greater than any resistor in the circuit
series
Series, parallel, or both? The largest resistor will use the greatest amount of power
series
Series, parallel, or both? The smallest resistor will receive the smallest voltage
series
T/F: Current can have units of C/s
true
T/F: Current is defined as the rate of flow of electric charges
true
T/F: Currents can only travel through closed loops, called circuits
true
T/F: Currents come in two "varieties" : AC and DC
true
T/F: Home electrical wiring is done in parallel so that each device receives the same voltage.
true
T/F: Home electrical wiring is done in parallel so that if many devices are running, the current is not reduced to unusable levels.
true
T/F: Home electrical wiring is done in parallel so that some devices may be on while others are off
true
T/F: In regards to a series circuit, as more light bulbs are added, the total current decreases
true
T/F: In regards to resistors wired in parallel, the Req decreases as more resistors are added
true
T/F: The conventional current is opposite to the actual current of electrons in a circuit
true
T/F: The conventional current is the current that always exits from the positive terminal of the battery
true
T/F: The conventional current is the direction of flow of positive charges in a circuit
true
T/F: The flow of current is different through resistors that are connected in parallel
true