Question
Download Solution PDFThe electric field in an electro-magnetic wave (in vacuum) is described by E = Emax sin(Kx - ωt)
Where
Emax = 100 N/C and K = 1 × 107 m-1, speed of light is 3 × 108 m/s.
What is the amplitude of the corresponding magnetic wave?
Answer (Detailed Solution Below)
Detailed Solution
Download Solution PDFConcept:
The intrinsic impedance of the wave is defined as the ratio of the electric field and the magnetic field phasor (complex amplitude), i.e.
\(η =\frac{E}{H}\)
For free-space, the intrinsic impedance is a real quantity, i.e.
η = η0 = 120π
Analysis:
E = Emax sin(Kx - ωt)
With Emax = 100 N/C, the magnetic field will be:
With \(η =\frac{E}{H}\):
\(H =\frac{E}{\eta}\)
\(H =\frac{100}{120\pi}A/m\)
B = μ0 H
\(B=4\pi × 10^{-7}× \frac{100}{120\pi }\)
B = 3.33 × 10-7 T
Last updated on Jul 2, 2025
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