Everything Science Grade 10

CHAPTER 17. ELECTRIC CIRCUITS 17.1

EMF ESAFC

When you measure the potential difference
across (or between) the terminals of a battery
that isnot in a complete circuityou are mea-
suring the emf of the battery. This is the maxi-
mum amount of work per coulomb of charge
the battery can do to drive charge from one
terminal, through the circuit, to the other ter-
minal.

V

FACT

The volt is named af-

ter the Italian physi-

cist Alessandro Volta

(1745–1827).

Electrical potential difference is also called voltage.

When you measure the potential difference
across (or between) the terminals of a battery
that isin a complete circuityou are mea-
suring the terminal potential difference of the
battery. Although this is measured in volts it
is not identical to the emf. The difference will
be the work done to drive charge through the
battery.

V

Batteries

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One lead of the voltmeter is connected to

one end of the battery and the other lead

is connected to the opposite end. The volt-

meter may also be used to measure the volt-

age across a resistor or any other component

of a circuit but must be connected in parallel.

Physics: Electricity and Magnetism 281