KCET2021PhysicsElectromagnetic Waves
Suppose that the electric field amplitude of electromagnetic wave is E₀=120 NC ⁻¹ and its frequency f=50 MHz . Then, which of the following value is incorrectly computed?
Options
- AMagnetic field amplitude is 400 nT .
- BAngular frequency of EM wave is 10⁸ rad / s .
- CPropagation constant (angular wave number) is 2.1 rad / m .
- DWavelength of EM wave is 6 ~m .
Correct answer
C. Propagation constant (angular wave number) is 2.1 rad / m .
Step-by-step solution
Given, E₀=120 NC ⁻¹f=50 MHz =50 10⁶ ~Hz (a) magnetic field amplitude, aligned B₀ &= E₀ c = 120 3 10⁸ =40 10⁻⁸ ~T &=400 n T aligned (b) Angular frequency, =2 f=2 50 10⁶= 10⁸ rad / s (c) Propagation constant, k= c = 10⁸ 3 10⁸ =1.047 rad / m (d) Wavelength, = c f = 3 10⁸ 50 10⁶ = 30 5 =6 ~m