Physics 9702 · AS & A Level · Force on a moving charge
Force on a moving charge — practice question
Fig. 6.1 depicts a thin semiconducting slice used in a Hall probe. Current $I$ flows through the slice in the direction indicated. The slice is set in a uniform magnetic field of flux density $B$, with two of its faces perpendicular to the magnetic field. A constant Hall voltage $V_H$ appears between face $PQXW$ and face $SRYZ$.
(a(i))[1]
Use the letters in Fig. 6.1 to identify the faces that lie perpendicular to the magnetic field.
(a(ii))[3]
Explain how the steady Hall voltage $V_H$ forms between faces $PQXW$ and $SRYZ$.
(b(i))[3]
The magnitude of $V_H$ is given by the equation $V_H = \frac{BI}{ntq}$. State the meanings of $n$, $t$ and $q$. You may refer to the letters in Fig. 6.1.
(b(ii))[2]
Suggest, with reference to the equation, why the material slice used in a Hall probe is thin.
Worked solution & mark scheme
This 9-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Faces PQRS and WXYZ correctly identified” …