Dodd I. Chemistry and Electrochemistry 1969 torrent

Textbook in PDF format

As you well know, when we warn an ordinary torch battery to produce a current we join the two terminals of ihc battery with a wire or a torch bulb in order to complete a circuit. When the circuit is made, current flows, and die bulb lights. But even in the inactive battery the tendency for current to flow is present, waiting for the circuit to be completed. This tendency is known as 'electromotive force. It is measured by the potential difference between, the terminals of a cell when no current is being taken from it. The electromotive force is the ability of a source of electricity to set a current flowing once a suitable circuit is completed. Tn. any circuit the current flowing is determined partly by the electromotive force available. In general the higher the e.m.f., i he larger the current. But a circuit also has a resistance, and rhe higher the resistance the smaller the current. These three factors are linked together:
current (in amperes) = e.m.f. (in volts)
x total resistance (in ohms)
or e.m.f, = current X resistance
volts — amperes x ohms
Electromotive force is something that a source of electricity has at all times. Resistance is something that a circuit has at all times. But a current is only obtained if a source of electricity is connected into a circuit. Additionally, an educational film about the device of an electrical batteryes, duration 10 minutes, is posted