WTMA Basic Electrical Principles 3 โ Questions and Answers
Question 1: What is the electrical resistance of a perfect conductor?
- Zero ohms (Correct answer)
- Infinite ohms
- One ohm
- It depends on voltage
Correct answer: Zero ohms
A perfect conductor has zero resistance, allowing current to flow without any opposition or energy loss.
Question 2: A 120-volt circuit draws 2 amperes of current. What is the power consumption?
- 240 watts (Correct answer)
- 60 watts
- 122 watts
- 118 watts
Correct answer: 240 watts
Power (P) = Voltage (V) ร Current (I) = 120 V ร 2 A = 240 watts.
Question 3: What happens to total resistance when resistors are added in parallel?
- Total resistance decreases (Correct answer)
- Total resistance increases
- Total resistance stays the same
- Total resistance doubles
Correct answer: Total resistance decreases
Adding resistors in parallel creates more paths for current, which reduces the overall resistance of the circuit.
Question 4: Which of the following is an example of an electrical insulator?
- Plastic (Correct answer)
- Aluminum
- Iron
- Salt water
Correct answer: Plastic
Plastic has very high resistance and does not allow current to flow easily, making it a good insulator.
Question 5: A battery's voltage represents which of the following?
- The electrical pressure that pushes current through a circuit (Correct answer)
- The amount of charge stored
- The resistance of the battery
- The current the battery provides
Correct answer: The electrical pressure that pushes current through a circuit
Voltage (electromotive force) is the electrical pressure or potential difference that drives current through a circuit.
Question 6: What is the relationship between watts, volts, and amps described by?
- P = V ร I (Correct answer)
- P = V / I
- P = I / V
- P = V + I
Correct answer: P = V ร I
The power formula P = V ร I (Power equals Voltage times Current) is fundamental to electrical calculations.
Question 7: If a 12-volt battery is connected to a 4-ohm resistor, how much current flows?
- 3 amperes (Correct answer)
- 48 amperes
- 8 amperes
- 0.33 amperes
Correct answer: 3 amperes
Using Ohm's Law: I = V/R = 12 V รท 4 ฮฉ = 3 amperes.
WTMA Basic Electrical Principles 3
What is the electrical resistance of a perfect conductor?