| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.14 |
| Score | 0% | 63% |
The conductivity of an element depends on how many electrons occupy which electron shell?
outer |
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middle |
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inner |
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first |
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.
Which of the following is not a characteristic of a step-up transformer?
the primary voltage is higher than the secondary voltage |
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the secondary voltage is higher than the primary voltage |
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has more turns in the secondary winding than in the primary winding |
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increases voltage |
As their names indicate, a step-up transformer is used to step up or increase voltage and a step-down transformer is used to step down or decrease voltage. In a step-up transformer, the secondary voltage is higher than the primary voltage and it has more turns in the secondary winding than in the primary winding.
Which of the following will increase the magnetic field produced by the electric current in a wire?
construct the wire from conductive material |
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wind the wire into a coil |
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construct the wire from insulative material |
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wrap the wire around a ceramic core |
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.
Inductance is a factor in which of the following?
batteries connected in serial |
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a DC circuit |
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an AC circuit |
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determining energy stored by a capacitor |
Inductance is a property of an AC circuit (or a component in an AC circuit) that quantifies resistance to changes in current. The current in an AC circuit is continuously changing and inductive reactance (the opposition to change) depends both on the inductance of the circuit or component and the rate at which the current is changing.
You would measure the amount of current through a circuit with a(n):
voltmeter |
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potentiometer |
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ammeter |
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battery |
Current is the rate of flow of electrons per unit time and is measured in amperes (A). An ammeter is used to measure the electric current in a circuit.