FAA Aviation Mechanic General (AMG)Fundamentals of Electricity and ElectronicsEasy
A technician measures a 4-ohm resistor with 12 volts applied across it. What is the current flowing through the resistor?
- A16 A
- B0.33 A
- C3 A
- D48 A
Show answer & explanationAnswer & explanation
Correct answer: C. 3 A
Using Ohm's Law, I = E/R = 12V / 4Ω = 3 amperes.
Why the other options are wrong
- A. This results from adding instead of dividing.
- B. This is R/E, an inverted calculation.
- D. This is E × R, not E/R.
Ohm's Law
The relationship between voltage, current, and resistance in a DC circuit: E = I × R.
- E = voltage in volts
- I = current in amperes
- R = resistance in ohms
- Rearranged forms: I=E/R and R=E/I
Memory trick: E is up top, I and R hold hands below — cover E to get I×R.