2.1 Introduction
2.2 Generation of Electromagnetic Waves
2.2.1 Speed of Electromagnetic Waves
2.2.2 Direction of Propagation of Electromagnetic Waves
2.2.3 Doppler Effect of Electromagnetic Waves
2.3 The Electromagnetic Spectrum
2.4.1 Energy Carried by Electromagnetic Waves
2.4.2 Radiation Pressure
2. Summary
Unit 2 - Multiple Choice - Electromagnetic Waves Questions
Unit 2 - Multiple Choice - Electromagnetic Waves Answers
Unit 2.1 Multiple Choice Extended Questions - Waves
Unit 2.1 Multiple Choice Extended Answers-Waves
 

Unit 2 Electromagnetic Waves

2.4 Energy and Momentum in Electromagnetic Waves

2.4.2 Energy Carried by Electromagnetic Waves

The intensity of a wave I =[P/A]Avg

When the EM waves strike at non-normal incidence replace A with Acosθ.

This is a measure of how much energy strikes a surface of area A every second for normal incidence.

surface em

Example 1.

The Sun delivers about 1.0X103 Wm-2 of energy to the Earth’s surface via electromagnetic radiation. What is the power incident on a car park 8.00m X 20.0m by the overhead sun.

Pavg = I X A

Pavg = 1.0X103 Wm-2 X 8.00m X 20.0m

Pavg = 1.60 X 105 W

Question: Compare this to the energy needs for your home.

 

     
Concept by Kishore Lal. Programmed by Kishore Lal... Copyright © 2015 Kishore Lal. All rights reserved.