Measurement of resistance and potential difference

To compare the e.m.f.s of two cells by using a potentiometer

To compare the e.m.f.s of two cells by using a potentiometer In the circuit diagram of Fig. 40.7 the points D and F may be considered as the two terminals of a voltmeter. D is connected directly to ·A, and F is connected to a sliding contact on the potentiometer wire via a sensitive centre-zero galvanometer. As …

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The potentiometer

The potentiometer The potentiometer is a piece of apparatus for comparing potential differences. The simple potentiometer used in elementary work consists of a length of one or more metres of uniform resistance wire mounted on a board between thick brass or copper strips of negligible resistance. A millimetre scale is fixed to the board for measuring the distance from …

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Factors affecting the resistance of a wire at constant temperature

Factors affecting the resistance of a wire at constant temperature When resistors are being made, short lengths of thick wire are used for the low resistances and long lengths of thin wire for the high resistances. Besides length and thickness the material of which the wire is composed is another important factor to be considered when deciding the …

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Resistance of an electric lamp and other conductors

Resistance of an electric lamp and other conductors The ammeter-voltmeter method is an excellent one for measuring the resistance of an electric lamp when run at different voltages. The circuit shown in Fig. 40.4 (a) is used in which the single cell is replaced by any convenient 6 V d.c. source and the resistor R changed for a …

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