| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.21 |
| Score | 0% | 64% |
From what energy do photovoltaic cells produce electrical energy?
magnetic |
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sun |
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chemical |
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nuclear |
A photovoltaic cell (also known as a solar cell) converts energy from the sun into electrical energy.
Which of the following will help to prevent a short circuit?
resistor |
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transistor |
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diode |
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fuse |
Fuses are thin wires that melt when the current in a circuit exceeds a preset amount. They help prevent short circuits from damaging circuit components when an unusually large current is applied to the circuit, either through component failure or spikes in applied voltage.
A capacitor is often used for which of the following purposes?
to maintain power in a circuit when the primary power source is disconnected |
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to allow a small amount of current to control a large amount of current |
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as a primary power source |
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to convert alternating current into direct current |
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 are often used to maintain power within a system when it is disconnected from its primary power source or to smooth out or filter voltage within a circuit.
The voltage output of a transformer primarily depends on which of the following?
the conductor used for the wire in the coils |
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the diameter of the wire in the coils |
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the number of turns in the wire of the coils |
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the diameter of the coils |
A transformer utilizes an inductor to increase or decrease the voltage in a circuit. AC flowing in a coil wrapped around an iron core magnetizes the core causing it to produce a magnetic field. This magnetic field generates a voltage in a nearby coil of wire and, depending on the number of turns in the wire of the primary (source) and secondary coils and their proximity, voltage is induced in the secondary coil.
The sum of the voltage drops across each resistor in a __________ circuit will equal the total voltage applied to the circuit.
series |
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parallel |
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closed |
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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.