Final answer:
The physical intensity of a stimulus affects the rate of action potentials and the number of receptors activated, which contributes to the perceived intensity of the stimulus.
Step-by-step explanation:
The relationship between the physical intensity and the perceived intensity of a stimulus is that an intense stimulus will produce a more rapid train of action potentials, while reducing the stimulus will slow the rate of production of action potentials. Another way intensity is encoded is by the number of receptors activated. An intense stimulus might initiate action potentials in a large number of adjacent receptors, while a less intense stimulus might stimulate fewer receptors.