Electrons enter a rectangular slice PQRSEFGH of a semiconductor material at right-angles to face PQFE, as shown in Fig. 8.1. [Figure 8.1] A uniform magnetic field of flux density B is directed into the slice, at right-angles to face PQRS.

1. (a)The electrons each have charge –q and drift speed v in the slice. State the magnitude and the direction of the force due to the magnetic field on each electron as it enters the slice.[2]
2. (b)(i)State the two faces between which the voltage V_H is established. face ..................................................... and face ..................................................... [1][1]
3. (b)(ii)Use letters from Fig. 8.1 to identify the distance t.[1]
4. (c)(i)Show that the number of charge carriers per unit volume in aluminium is 6.0 × 10²⁸ m⁻³.[2]
5. (c)(ii)A sample of aluminium foil has a thickness of 0.090 mm. The current in the foil is 4.6 A. A uniform magnetic field of flux density 0.15 T acts at right-angles to the foil. Use the value in (i) to calculate the voltage V_H that is generated. V_H = ..................................................... V [2][2]

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