Electric Circuits
A circuit has a current of 3 A and a voltage of 12 V. What is the electric power?
4 W
9 W
15 W
36 W
A light bulb with a power rating of 75 W is connected to a 120 V source. What is the resistance of the bulb?
57.6
192
240
160
A heating element in a kettle has a resistance of 20 and is connected to a 120 V power supply. What is the power consumed by the heating element?
6 W
240 W
720 W
1440 W
Two resistors, one with a resistance of 4 and the other with a resistance of 6 , are connected in series to a 12 V battery. What is the power dissipated by the 4 resistor?
1.6 W
2.4 W
5.76 W
8.64 W
A 60 W light bulb is connected in parallel with a 100 W light bulb to a 120 V source. Which bulb will be brighter?
The 60 W bulb.
The 100 W bulb.
They will have the same brightness.
The brightness depends on the internal resistance of the source.
A light bulb is labeled '60 W'. What does this indicate about the bulb?
It consumes 60 joules of energy per second.
It has a resistance of 60 ohms.
It requires a current of 60 amperes.
It emits 60 candelas of light.
Two light bulbs have power ratings of 60 W and 100 W, respectively. Both are connected to a 120 V source. Which bulb will be brighter?
The 60 W bulb.
The 100 W bulb.
They will have the same brightness.
Brightness depends on the resistance.

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A circuit contains two light bulbs. Bulb A has a resistance of 10 , and Bulb B has a resistance of 20 . If both bulbs are connected in series, which bulb will dissipate more power and thus be brighter?
Bulb A.
Bulb B.
Both bulbs will have the same brightness.
Cannot determine without knowing the voltage.
Which of the following best describes electric power?
The total amount of electrical energy in a circuit.
The rate at which electrical energy is transferred or dissipated.
The opposition to the flow of current in a circuit.
The electric potential difference between two points in a circuit.
A device has a current of 4 A flowing through it and a resistance of 5 . What is the power dissipated by the device?
10 W
20 W
40 W
80 W