| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.03 |
| Score | 0% | 61% |
What is the voltage of most household electrical systems in the United States?
60V |
|
220V |
|
60Hz |
|
110V |
Most households use electricity with a voltage of 110V.
Direct current flows from the __________ terminal of the voltage source to the __________ terminal.
positive, positive |
|
negative, negative |
|
positive, negative |
|
negative, positive |
Direct current flows in only one direction in a circuit, from the negative terminal of the voltage source to the positive. A common source of direct current (DC) is a battery.
In an electrical circuit, resistors have fixed or __________ resistance.
series |
|
variable |
|
dynamic |
|
parallel |
Resistors are used to limit voltage and/or current in a circuit and can have a fixed or variable resistance. Variable resistors (often called potentiometers or rheostats) are used when dynamic control over the voltage/current in a circuit is needed, for example, in a light dimmer or volume control.
A __________ electric current produces a magnetic field proportional to the amount of current flow.
moving |
|
high voltage |
|
stationary |
|
low voltage |
A moving electric current produces a magnetic field proportional to the amount of current flow. This magnetic field can be made stronger by winding the wire into a coil and further enhanced if done around an iron containing (ferrous) core.
The valence shell of a conductor is how full of electrons?
less than half full |
|
half full |
|
more than half full |
|
full |
Conductors are elements that allow electrons to flow freely. Their valence shell is less than half full of electrons that are able to move easily from one atom to another.