| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.11 |
| Score | 0% | 62% |
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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wrap the wire around a ceramic core |
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wind the wire into a coil |
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construct the wire from insulative material |
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 n insulator is how full of electrons?
more than half full |
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empty |
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less than half full |
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half full |
Insulators have valence shells that are more than half full of electrons and, as such, are tightly bound to the nucleus and difficult to move from one atom to another.
The sum of the voltage drops across each resistor in a __________ circuit will equal the total voltage applied to the circuit.
parallel |
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closed |
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series |
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series-parallel |
A series circuit has only one path for current to flow. In a series circuit, current (I) is the same throughout the circuit and is equal to the total voltage (V) applied to the circuit divided by the total resistance (R) of the loads in the circuit. The sum of the voltage drops across each resistor in the circuit will equal the total voltage applied to the circuit.
Which of the following is a difference between a circuit breaker and a fuse?
all of these |
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a fuse responds more quickly than a circuit breaker |
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a circuit breaker can be reused |
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a fuse is cheaper than a circuit breaker |
Like fuses, circuit breakers stop current flow once it reaches a certain amount. They have the advantage of being reusable (fuses must be replaced when "blown") but respond more slowly to current surges and are more expensive than fuses.
Which of the following is not a characteristic of a step-up transformer?
increases voltage |
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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 |
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.