FAA Aviation Mechanic General (AMG)Fundamentals of Electricity and ElectronicsEasy
A technician is installing a new navigation light bulb rated at 28 volts and 0.5 amperes. What is the resistance of the bulb's filament when it is operating normally?
- A28 ohms
- B112 ohms
- C14 ohms
- D56 ohms
Show answer & explanationAnswer & explanation
Correct answer: D. 56 ohms
Using Ohm's Law (R = V/I), where V is 28 volts and I is 0.5 amperes, the resistance (R) is 28V / 0.5A = 56 ohms.
Why the other options are wrong
- A. Incorrectly calculated (e.g., V / I but with an error, or just V).
- B. Incorrectly calculated (e.g., V / I * 2).
- C. Incorrectly calculated (e.g., V * I or I / V).
Ohm's Law (Resistance)
Ohm's Law states that the current through a conductor between two points is directly proportional to the voltage across the two points and inversely proportional to the resistance between them. When finding resistance, R = V/I.
- R = Resistance (ohms Ω)
- V = Voltage (volts V)
- I = Current (amperes A)
Memory trick: V over I times R, the voltage triangle's star.