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Show that for a continuous sinusoidal electromagnetic wave, the peak intensity is twice the average intensity (I0=2Iave), using either the fact that E0=2Erms,orB0=2Brms, where rms means average (actually root mean square, a type of average).

Short Answer

Expert verified

The solution isI0=2Iavg .

Step by step solution

01

Define electromagnetic waves

Electromagnetic waves, or EM waves, are waves that are formed when an electric field and a magnetic field vibrate together.

02

Explanation

It is known that a wave's intensity is related to its amplitude squared and is given by

I0=kE02

Where I0is peak intensity, k is proportionality constant, E0is peak electric field strength.

And the average intensity is calculated as

Iavg=kErms2

Where Iavgis average intensity, k is proportionality constant, Erms is average electric field strength.

Therefore,

I0Iavg=kE02kErms2

Substitute the value of E0=2Ermsin the above equation,

I0Iavg=kE02kErms2I0Iavg=2Erms2Erms2I0Iavg=2I0=2IavgTherefore,I0=2Iavg.

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