Ohm’s law describes the mathematical relationship
between voltage, current and resistance in a circuit.
Ohm determined that if the voltage across a resistor is
increased, the current through the resistor will increase
and conversely, if the voltage is decreased the current
will decrease. Ohm’s law also shows that if the voltage
(V) is kept constant, less resistance (R) results in more
current (I), and more resistance results in less current.
Ohm’s law can be stated as follows:
I ¼
V
R
or V ¼ I R or R ¼
V
I
: ð2Þ
Electrolyte solutions also obey Ohm’s law just as
metallic conductors do. From a macroscopic point of
view, ionic conduction of solutions is similar to electron
conduction through solid objects. In the latter, electrons
are moving without ion cores, whilst in the
former, charges are moving as ions. Although water
itself is a poor conductor of electricity, the presence of
ions in solution decreases the resistance considerably.
The resistance of such electrolytic solutions depends on
the concentration of the ions and also on the nature
and size of the ions present.