| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.18 |
| Score | 0% | 64% |
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 rate of flow of electrons per unit time is which of the following?
current |
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conductance |
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resistance |
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voltage |
Current is the rate of flow of electrons per unit time and is measured in amperes (A). A coulomb (C) is the quantity of electricity conveyed in one second by a current of one ampere.
In metals, increasing the temperature typically _____________ conductivity.
eliminates |
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decreases |
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does nothing to |
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increases |
All conductors have resistance and the amount of resistance varies with the element. Metals exhibit increased resistance (and, therefore, lower conductivity) as their temperature increases.
What type of current flows in only one direction in a circuit?
alternating |
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direct |
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parallel |
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series |
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.
Capacitors connected in series produce __________ capacitance compared to capacitors connected in parallel.
more |
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the same |
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no |
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less |
Capacitors store electricity and are used in circuits as temporary batteries. Capacitors are charged by DC current (AC current passes through a capacitor) and that stored charge can later be dissipated into the circuit as needed. Capacitors connected in series produce less capacitance than capacitors connected in parallel.