Question

In a wave $E_0=100{Vm}^{-1}$. Find the Poynting vector magnitude.

• A. $13.25{Wm}^{-2}$
• B. $26.5{Wm}^{-2}$
• C. $18.25{Wm}^{-2}$
• D. $19.7{Wm}^{-2}$

Answer 1

The correct option is B $26.5{Wm}^{-2}$

$B=\frac{E}{c}$

$⟹\left|\overrightarrow{p}\right|=\frac{EB}{{\mu }_0}=\frac{E^2}{c{\mu }_0}$

$=\frac{{10}^4}{3\times {10}^8\times 4\pi \times {10}^{-7}}=26.5W{m}^{-2}$