A potentiometer is connected to a battery of electromotive force (e.m.f.) 9.6V and negligible internal resistance, as shown in Fig. 7.1. [Figure 7.1] The maximum resistance of the potentiometer is 800 Ω. A resistor R of resistance 400 Ω is connected between the slider and end X of the potentiometer.

1. (a)State Kirchhoff's first law.[1]
2. (b)(i)1.State the potential difference across resistor R when the slider is positioned 1. at end X of the potentiometer, potential difference = ..................................................... V[2]
3. (b)(i)2.2. at end Y of the potentiometer. potential difference = ..................................................... V[2]
4. (b)(ii)Calculate the potential difference across resistor R when the slider is positioned half-way between X and Y. potential difference = ..................................................... V[3]

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