| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.66 |
| Score | 0% | 73% |
One of the lights on your Christmas tree burns out and this causes the rest of the lights connected to that strand to go dark. How are the lights in that strand connected?
series |
|
perpendicular |
|
parallel |
|
series-parallel |
Lights connected in series form a chain with each light connecting to adjacent lights via one wire. Therefore, if one of the lights burns out and breaks the series, none of the other lights will receive power and they'll go dark. Lights connected in parallel each connect to the positive and negative nodes of the power source and would not go dark if one of their neighbors burnt out.
Using a fuse with a current rating higher than that required by a circuit:
makes the circuit less safe |
|
is recommended |
|
makes no difference |
|
is required |
A fuse is a type of low resistance resistor that stops current flow in a circuit in response to a larger than intended electric current flow. Using a fuse with a higher current rating than required by a circuit is less safe as it could potentially allow overcurrent and risk a fire or heat-related equipment damage.
An inductor __________ changes in the electric current flowing through it.
doubles |
|
eliminates |
|
resists |
|
enhances |
An inductor is coiled wire that stores electric energy in the form of magnetic energy and resists changes in the electric current flowing through it. If current is increasing, the inductor produces a voltage that slows the increase and, if current is decreasing, the magnetic energy in the coil opposes the decrease to keep the current flowing longer. In contrast to capacitors, inductors allow DC to pass easily but resist the flow of AC.
Alternating current changes __________ many times each second.
direction |
|
resistance |
|
period |
|
frequency |
In contrast to the constant one-way flow of direct current, alternating current changes direction many times each second. Electricity is delivered from power stations to customers as AC because it provides a more efficient way to transport electricity over long distances.
All electricity is the movement of which subatomic particles?
protons |
|
electrons |
|
neutrons |
|
nuclei |
All electricity is the movement of electrons which are subatomic particles that orbit the nucleus of an atom. Electrons occupy various energy levels called shells and how well an element enables the flow of electrons depends on how many electrons occupy its outer (valence) electron shell.