For the free electrons moving in the slice, state the direction of the force on an electron due to the electron’s motion in the magnetic field.
Using the labels on Fig. 8.1, identify the faces between which a potential difference is produced.
Explain why the potential difference in (a)(ii) reaches a maximum value.
The number of free electrons per unit volume in the slice of material is $1.3 \times 10^{29}\,\text{m}^{-3}$. The thickness $PQ$ of the slice is $0.10\,\text{mm}$. The magnetic flux density $B$ is $4.6 \times 10^{-3}\,\text{T}$. Calculate the potential difference across the slice for a current of $6.3 \times 10^{-4}\,\text{A}$.
The slice in part (c) is a metal. Using your answer to part (c), suggest why Hall probes are generally made from semiconductors rather than metals.