Engineering Physics: Unit II: Electromagnetic Waves

Intensity of an Electromagnetic wave in vacuum

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The magnitude of the average value of at a point is called the intensity of radiation at that point.

INTENSITY OF AN EM WAVE IN VACUUM

The magnitude of the average value of at a point is called the intensity of radiation at that point. The S.I unit of intensity is W/m2.

Let us consider the electric and magnetic field solutions

and

From eqn. (6)

The x-component (Direction of propagation) of the poynting vector is given as

The time average value of cos 2 (ωt - kx) is zero. So the average value of the poynting vector is

This is the intensity of an EM wave in vacuum.

Also intensity is represented as for localised sources as

Engineering Physics: Unit II: Electromagnetic Waves : Tag: : - Intensity of an Electromagnetic wave in vacuum

Home | Department: Mech Department | Ist Year | Subject: Engineering Physics |

Next >>

Electromagnetic Waves - Introduction

Maxwell's Equations - Integral form, Statement, Characteristics

Wave Equation - Maxwell's equations | Electromagnetic Waves

Speed (velocity) of EM wave in vacuum - Electromagnetic Waves

Conditions on the Wave Field

Phase and Orientation of Electromagnetic wave in matter

Propagation of Electromagnetic wave through a Dielectric medium (non - conducting isotropic medium)

EM waves in conducting medium (medium with finite μ, ε and σ) - Electromagnetic Waves

Properties of Electromagnetic Waves

Localized sources for electromagnetic waves

Polarization - Electromagnetic Waves

Producing electromagnetic waves - Hertz experiment

Electromagnetic Energy flow and Poynting Vector - Electromagnetic Waves

Intensity of an Electromagnetic wave in vacuum

Momentum and radiation pressure - Electromagnetic Waves

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