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An electromagnetic plane wave has an intensity Sₐᵥₑᵣₐₑ = 700 W/m².

What are the Erms values Brms and Brms of the electric and magnetic fields, respectively?

User Domruf
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The root mean square (rms) electric field is determined as 513.47 N/C.

The root mean square (rms) magnetic field is determined as 1.71 x 10⁻⁶ T.

How to calculate the root mean electric field and magnetic field.

The root mean square (rms) electric field is calculated by applying the following formula as shown below.

S = cε₀E²

where;

  • c is the speed of light
  • ε₀ permittivity of free space
  • E is the root mean square electric field.

E² = (S) / (cε₀)

E = √ [(S) / (cε₀)]

E = √[ (700) / (3 x 10⁸ x 8.85 x 10⁻¹²) ]

E = 513.47 N/C

The root mean square (rms) magnetic field is calculated by applying the following formula.

S = cB² / μ

B² = Sμ / c

B = √ (Sμ / c)

B = √( (700 x 4π x 10⁻⁷) / (3 x 10⁸) )

B = 1.71 x 10⁻⁶ T

User Cerebrate
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