EIAT Basic Electrical Principles 3 — Questions and Answers
Question 1: What does a diode primarily do in an electrical circuit?
- Amplifies voltage
- Allows current to flow in only one direction (Correct answer)
- Stores electrical charge
- Regulates resistance
Correct answer: Allows current to flow in only one direction
A diode is a semiconductor device that permits current to flow in one direction only, acting as a one-way valve.
Question 2: What is the relationship between voltage (V), current (I), and resistance (R) in Ohm's Law?
- V = I + R
- V = I × R (Correct answer)
- V = I / R
- V = R / I
Correct answer: V = I × R
Ohm's Law states that voltage equals current multiplied by resistance: V = I × R.
Question 3: Which component is used to protect a circuit from excess current by breaking the circuit?
- Capacitor
- Transformer
- Fuse (Correct answer)
- Resistor
Correct answer: Fuse
A fuse contains a metal element that melts and breaks the circuit when current exceeds a safe level.
Question 4: What is the voltage across a 15-ohm resistor carrying 3 amperes of current?
- 5 V
- 18 V
- 45 V (Correct answer)
- 0.2 V
Correct answer: 45 V
Using Ohm's Law: V = I × R = 3 × 15 = 45 V.
Question 5: In electrical terms, what is 'grounding' primarily intended to do?
- Increase circuit efficiency
- Provide a safe path for fault current to prevent shock (Correct answer)
- Boost signal strength
- Reduce voltage fluctuations
Correct answer: Provide a safe path for fault current to prevent shock
Grounding provides a low-resistance path for fault current to flow safely to earth, protecting people from electric shock.
Question 6: What type of device converts AC voltage from one level to another?
- Rectifier
- Inverter
- Transformer (Correct answer)
- Oscillator
Correct answer: Transformer
A transformer uses electromagnetic induction to step AC voltage up or down between two or more coils.
Question 7: Which material is classified as a semiconductor?
- Copper
- Silicon (Correct answer)
- Rubber
- Steel
Correct answer: Silicon
Silicon is the most widely used semiconductor material because its conductivity can be precisely controlled by doping.
EIAT Basic Electrical Principles 3
What does a diode primarily do in an electrical circuit?