Final answer:
Voltage sags are temporary decreases in power line voltage caused by the start-up power demands of many electrical devices.
Step-by-step explanation:
Voltage drops caused by the start-up power demands of many electrical devices are known as voltage sags. These are temporary decreases in power line voltage that occur when multiple devices are turned on simultaneously. The voltage drop is proportional to the current, resulting in a decrease in power output by the appliances. For example, if there is a large voltage drop across an extension cord, the voltage drop across the appliance will be significantly decreased, reducing its ability to work properly.