Electronics MCQ Quiz – Part 2
21. A component that converts chemical energy into electrical energy is known as a:
Correct Answer: C) Battery
Batteries produce electrical energy from chemical reactions inside their cells.
22. Which of the following is a semiconductor?
Correct Answer: C) Silicon
Silicon’s conductivity sits between conductors and insulators, making it ideal for electronic devices.
23. A solid state diode has no filament. Which statement is true as a result?
Correct Answer: C) It requires less operating power
Solid-state diodes do not need filament heating, so they use less power than vacuum tubes.
24. Which of the following is used to measure electrical resistance?
Correct Answer: B) Ohmmeter
An ohmmeter reads resistance in ohms. Voltmeters measure voltage and ammeters measure current.
25. Which of the following is NOT a type of resistor?
Correct Answer: B) Dielectric
Dielectric is an insulating material used in capacitors, not a resistor type. Potentiometers and rheostats are resistor types.
26. What is the purpose of a fuse in an electrical circuit?
Correct Answer: D) To protect the circuit from excessive current
Fuses break the circuit when current exceeds a safe level, preventing damage.
27. What is the symbol for a capacitor in a schematic diagram?
Correct Answer: B) Two parallel lines
Two parallel lines represent a capacitor. A zigzag line usually shows a resistor.
28. What is the symbol with three descending lines of decreasing width in electronic diagrams?
Correct Answer: C) Ground
The stacked lines symbol indicates a ground or common reference point.
29. What tool is used to join two wires with melted metal?
Correct Answer: B) Soldering iron
A soldering iron melts solder so it bonds wires or components together.
30. Which device stores energy in a magnetic field?
Correct Answer: C) Inductor
Inductors store energy in a magnetic field created when current flows through their coil.
31. Which metal is commonly used for house wiring because it conducts well and is relatively inexpensive?
Correct Answer: C) Copper
Copper offers excellent conductivity and fair cost, so it is widely used in wiring.
32. Copper wire used for circuits is chosen primarily for which property?
Correct Answer: B) Low cost and good conductivity
Copper minimizes energy loss and is affordable, making it the usual choice for conductors.
33. Which statement about transformers in power systems is correct?
Correct Answer: B) They are used to step voltage up or down
Transformers change AC voltage levels using electromagnetic induction. They do not convert AC to DC.
34. What is the function of a transformer in a circuit?
Correct Answer: C) Increases or decreases the voltage of an AC current
Transformers transfer energy between coils to raise or lower AC voltages.
35. The amount of energy used by consumers in homes is measured in:
Correct Answer: D) Kilowatt-hours
Utility companies charge for energy use in kilowatt-hours, which measure energy over time.
36. In household electrical wiring, which color of insulation indicates the ‘hot’ wire?
Correct Answer: C) Black
In standard practice, black is commonly used for the hot conductor. Ground is green or bare, and neutral is white.
37. What is the total resistance of a circuit containing three resistors of 10 Ω, 20 Ω, and 30 Ω connected in series?
Correct Answer: A) 60 Ω
Series resistances add, so 10 + 20 + 30 = 60 Ω.
38. If two identical capacitors are connected in parallel, what happens to total capacitance compared with a single capacitor?
Correct Answer: C) Doubles
Capacitors in parallel add directly, so two identical caps equal twice the single value.
39. If a resistor has color bands of red, red, brown, and gold, what is its value and tolerance?
Correct Answer: B) 220 Ω with 5% tolerance
Color code: first band = first digit (red = 2), second band = second digit (red = 2), third band = multiplier (brown = ×10). So 22 × 10 = 220 Ω. Gold indicates ±5% tolerance.
40. AM radio stations broadcast in which frequency range?
Correct Answer: A) 530–1,700 kHz
The AM broadcast band runs roughly from 530 kHz up to 1,700 kHz.
Quick Study Notes
Review Ohm’s law frequently: V = I × R, I = V ÷ R, P = V × I. These are key for many ASVAB electronics questions.
Memorize units: volts (V) for voltage, amperes (A) for current, ohms (Ω) for resistance, watts (W) for power, and hertz (Hz) for frequency.
Learn component roles: resistors limit current, capacitors store charge, inductors store magnetic energy, diodes control direction, and transformers change AC voltage.
Practice resistor color codes for quick value decoding: black 0, brown 1, red 2, orange 3, yellow 4, and so on. Third band is multiplier.
Understand circuit types: series has one path so same current flows; parallel has multiple paths so components stay lit independently.
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