If the amplitude of the magnetic field in a travelling plane electromagnetic wave is $2.2 \times 10^{-4}…

If the amplitude of the magnetic field in a travelling plane electromagnetic wave is $2.2 \times 10^{-4} \mathrm{~T}$, then the intensity of the wave is nearly
  1. $5.8 \times 106 \mathrm{Wm}^{-2}$
  2. $4.2 \times 106 \mathrm{Wm}^{-2}$
  3. $1.2 \times 107 \mathrm{Wm}^{-2}$
  4. $8.8 \times 105 \mathrm{Wm}^{-2}$

Solution

$I=\frac{B_0^2 C}{2 \mu_0}=\frac{\left(2.2 \times 10^{-4}\right)^2 \times 3 \times 10^8}{2 \times 4 \pi \times 10^{-7}}$ $=5.8 \times 10^6 \mathrm{Wm}^{-2}$

Asked in: AP EAMCET 2022 (08 Jul Shift 1)

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