| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.20 |
| Score | 0% | 64% |
The formula specifying Ohm's law is which of the following?
V = IR |
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V = I2R |
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\(V = {R \over I}\) |
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\(V = {I \over R}\) |
Ohm's law specifies the relationship between voltage (V), current (I), and resistance (R) in an electrical circuit: V = IR.
The voltage output of a transformer primarily depends on which of the following?
the diameter of the wire in the coils |
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the conductor used for the wire in the coils |
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the diameter of the coils |
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the number of turns in the wire 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.
You would measure the amount of resistance at a certain point in a circuit with a(n):
ohmmeter |
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potentiometer |
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voltmeter |
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ammeter |
Resistance is opposition to the flow of current and is measured in ohms (Ω). An ohmmeter is used to measure the amount of resistance at a certain point in a circuit.
A capacitor is often used for which of the following purposes?
to convert alternating current into direct current |
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as a primary power source |
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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 |
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.
Which of the following is not a common type of battery?
wet cell |
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dry cell |
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deep-cycle |
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power-cycle |
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. The three most common types of batteries are dry cell (used in small devices like TV remotes), wet cell (used for cars), and deep-cycle (storage batteries used primarily for backup and emergency power).