Physics 9702 · AS & A Level · Force on a moving charge

Force on a moving charge — practice question

A narrow conducting strip is positioned at right angles to a uniform magnetic field of flux density $B$, as shown in Fig. 8.1.
(a)[1]

Between which faces is the Hall voltage $V_H$ developed?

(b(i))[3]

The current $I$ is carried by particles of charge $+q$ that travel at speed $v$ in the direction of the current. The number density of these charge carriers is $n$. Obtain an expression connecting the Hall voltage $V_H$ with $v$, $B$ and $d$, where $d$ is one dimension of the slice.

(b(ii))[2]

Use your answer in (b)(i) together with an expression for the current $I$ in the slice to derive $V_H = \frac{BI}{ntq}$. Show your steps.

(c)[2]

Explain why the Hall voltage is hard to detect in a thin slice of copper.

Worked solution & mark scheme

This 8-mark question has a full step-by-step worked solution and mark scheme. One marking point: The faces are DERQ and CFSP.

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