Answer: Positive on top (conventional current downward).
- A Positive on top (conventional current downward)
- B Negative on top, the polarity expected for electron majority carriers
- C Zero, as if the Hall voltage vanished regardless of carrier type
- D Depends on sample size, with no dependence on carrier sign at all
Correct answer: A. Positive on top (conventional current downward)
Explanation: Hall effect: positive holes drift and accumulate, creating Hall voltage. For p-type semiconductor, Hall voltage has different sign than n-type.
The magnetic field around a long straight current-carrying wire forms concentric circles, with direction given by the right-hand rule (point thumb along I, fingers curl in the direction of B).
Concept context
Magnetic force on moving charges and currents, the Biot-Savart law, Ampere's law, and the cyclotron - how electric currents create and respond to magnetic fields.