Polytechnic Electronics and Electrical Engineering 1 — Questions and Answers
Question 1: Which law states that the current through a conductor is directly proportional to the voltage across it, given constant temperature?
- Kirchhoff's Voltage Law
- Ohm's Law (Correct answer)
- Faraday's Law
- Coulomb's Law
Correct answer: Ohm's Law
Ohm's Law states V = IR, meaning current is directly proportional to voltage when resistance is constant.
Question 2: What is the unit of electrical resistance?
- Farad
- Henry
- Ohm (Correct answer)
- Siemens
Correct answer: Ohm
Electrical resistance is measured in Ohms (Ω), named after physicist Georg Simon Ohm.
Question 3: Three resistors of 6Ω each are connected in parallel. What is the equivalent resistance?
- 18Ω
- 6Ω
- 3Ω
- 2Ω (Correct answer)
Correct answer: 2Ω
For N equal resistors in parallel, equivalent resistance = R/N = 6/3 = 2Ω.
Question 4: What type of component stores energy in an electric field?
- Inductor
- Resistor
- Capacitor (Correct answer)
- Diode
Correct answer: Capacitor
A capacitor stores energy in an electric field between its plates, expressed as E = ½CV².
Question 5: What is the frequency of standard US household AC power?
- 50 Hz
- 60 Hz (Correct answer)
- 100 Hz
- 120 Hz
Correct answer: 60 Hz
Standard US household AC power operates at 60 Hz, completing 60 cycles per second.
Question 6: A semiconductor diode allows current to flow in which direction?
- From cathode to anode only
- In both directions equally
- From anode to cathode only (Correct answer)
- It blocks current in all directions
Correct answer: From anode to cathode only
A forward-biased diode allows conventional current to flow from anode (+) to cathode (-) only.
Question 7: Which type of transistor uses a base, collector, and emitter terminal?
- MOSFET
- JFET
- BJT (Bipolar Junction Transistor) (Correct answer)
- SCR
Correct answer: BJT (Bipolar Junction Transistor)
A Bipolar Junction Transistor (BJT) has three terminals: base, collector, and emitter.
Polytechnic Electronics and Electrical Engineering 1
Which law states that the current through a conductor is directly proportional to the voltage across it, given constant temperature?