Lesson: Energy, Power, and Intensity of Electromagnetic Waves
In this lesson, we will learn how to calculate the energy, power, and intensity of electromagnetic waves and the magnitude of the Poynting vector.
Sample Question Videos
Worksheet: 14 Questions • 2 Videos
An outdoor WiFi unit for a picnic area has a 100-mW output and a range of about 30 m. What output power would reduce its range to 12 m for use with the same devices as before? Assume there are no obstacles in the way and that microwaves into the ground are simply absorbed.
Two lightbulbs have electrical power inputs of 100 W and 75 W respectively. At what distance is the intensity of light produced by the 100 W lightbulb equal to the intensity of light 10.0 m away from the 75 W lightbulb? Assume that both lightbulbs have the same efficiency.
What is the intensity of an electromagnetic wave with a peak electric field strength of 125 V/m?