The oscillating magnetic field in a plane electromagnetic wave is given by By = \(5 × 10^{–6}\) \(sin\;1000\;π(5x – 4 × 108\;t)T\). The amplitude of electric field will be:
- \(15 × 10^2\) \(Vm^{–1}\)
- \(5 × 10^{–6}\) \(Vm^{–1}\)
- \(16 × 10^{12} \;Vm^{–1}\)
- \(4 × 10^2\) \(Vm^{–1}\)
The Correct Option is D
Solution and Explanation
We know that the Speed of light : \(c = \frac{ω }{ k}\)
= \(\frac{4 × 10^8}{5} = 0.8 × 10^8\) \(m/sec\)
Therefore, \(E_0 = cB_0\)
=\( 0.8 × 10^8 × 5 × 10^{–6}\)
= \(400\) \(V/m\)
= \(4 × 10^{–2}\)
Hence, the correct option is (D): \(4 × 10^{–2}\; Vm^{-1}\)
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Concepts Used:
Electromagnetic Spectrum
The term used by scientists to describe the entire range of light that exists is the electrostatic spectrum. Light is a wave of alternating electric and magnetic fields. The propagation of light doesn't vary from waves crossing an ocean. Like any other wave, light also has a few fundamental properties that describe it. One is its frequency. The frequency is measured in Hz, which counts the number of waves that pass by a point in one second.
The electromagnetic waves that your eyes detect are visible light and oscillate between 400 and 790 terahertz (THz). That’s several hundred trillion times a second.