The oscillating electric field of an electromagnetic wave is given by $E_y=30 \sin \left(2 \times 10^{11}…

The oscillating electric field of an electromagnetic wave is given by $E_y=30 \sin \left(2 \times 10^{11} t+300 \pi x\right) \mathrm{Vm}^{-1}$. Then, the value of wavelength of the electromagnetic wave is
  1. $5.67 \times 10^{-3} \mathrm{~m}$
  2. $6.67 \times 10^{-3} \mathrm{~m}$
  3. $66.7 \times 10^{-3} \mathrm{~m}$
  4. $7.66 \times 10^{-3} \mathrm{~m}$

Solution

From equation of wave,
$k=$ wave number $=300 \pi$
Also,
$\begin{aligned}
& k=\frac{2 \pi}{\lambda} \\
& \lambda=\frac{2 \pi}{k}=\frac{2 \pi}{300 \pi}=6.67 \times 10^{-3} \mathrm{~m}
\end{aligned}$

Asked in: AP EAMCET 2018 (23 Apr Shift 2)

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