FAA Aviation Mechanic General (AMG)Fundamentals of Electricity and ElectronicsHard
According to the left-hand rule for generators (based on electron flow theory), a conductor moves upward through a magnetic field with flux lines pointing to the right. Using the thumb for motion and forefinger for field direction, what does the middle finger indicate?
- AThe direction of conductor motion
- BThe direction of induced current flow
- CThe polarity of the magnetic poles
- DThe direction of the magnetic flux
Show answer & explanationAnswer & explanation
Correct answer: B. The direction of induced current flow
In the left-hand generator rule, the thumb points in the direction of conductor motion, the forefinger points in the direction of the magnetic field, and the middle finger points in the direction of induced current (electron flow).
Why the other options are wrong
- A. Motion direction is represented by the thumb, not the middle finger.
- C. Magnetic pole polarity is not directly indicated by this rule.
- D. Flux direction is represented by the forefinger, not the middle finger.
Left-Hand Generator Rule
A method using the left hand (electron flow theory) to determine the direction of induced current when a conductor moves through a magnetic field.
- Thumb = direction of motion
- Forefinger = direction of magnetic field
- Middle finger = direction of induced current
- Used to predict generator output polarity
Memory trick: Thumb moves, Forefinger points the field, Middle finger shows the current — 'FBI' backwards for electron flow.