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# Electronics Information Practice Problems for McGraw-Hill's ASVAB (page 2)

By McGraw-Hill Professional
Updated on Jun 26, 2011

1. D.The polarity, or direction of electron flow, alternates in AC. Choice B is something that happens with alternating current, but this is not the reason for the name.
2. D.Electricity is a form of energy, and a current is defined as a flow of electrons.
3. A.Batteries always produce direct current (DC).
4. B.Total voltage drop is the sum of the individual voltage drops.
5. C.Electrical pressure is what "pushes" current through a circuit.
6. B.Amperes = volts/ohms = 120/6 = 20.
7. D.When electricity goes through a coil of wire in a transformer, it creates a magnetic field. When this field interacts with another coil of wire, it induces an electric current.
8. A.Electric motors are based on magnetic repulsion.
9. B.A short circuit has no resistance.
10. D.A transformer changes both current and voltage.
11. A.A series circuit has only one pathway, so when switch is open, the whole circuit shuts down.
12. A.Voltage is the same at all points of a parallel circuit.
13. B.A switch in a series-parallel circuit can control some or all devices, depending on the way it's wired.
14. D.Dopants control the electrical properties of a semiconductor.
15. B.1/Rtotal = 1/R1 + 1/R2 + 1/R3 = 1/3 = 1/12 = 5/12. Solve for Rtotal to get 12/5 ohms.