Final answer:
The fourth band on a resistor represents its Tolerance, which is a measure of how much the actual resistance of the resistor may deviate from its stated value.
Step-by-step explanation:
The fourth band on a resistor represents its Tolerance. The tolerance is a measure of how much the actual resistance of the resistor may deviate from its stated value. It is usually expressed as a percentage. For example, if a resistor has a tolerance of +/- 5%, it means that its actual resistance can be 5% higher or 5% lower than the stated value.