Electromagnetic Waves Question 2
Question 2 - 2024 (27 Jan Shift 1)
A plane electromagnetic wave propagating in $x$-direction is described by
$E _y=\left(200 Vm^{-1}\right) \sin \left[1.5 \times 10^{7} t-0.05 x\right]$;
The intensity of the wave is :
(Use $\epsilon _0=8.85 \times 10^{-12} C^{2} N^{-1} m^{-2}$ )
(1) $35.4 Wm^{-2}$
(2) $53.1 Wm^{-2}$
(3) $26.6 Wm^{-2}$
(4) $106.2 Wm^{-2}$
Show Answer
Answer: (2)
Solution:
$I=\frac{1}{2} \varepsilon _0 E _0^{2} \times c$
$I=\frac{1}{2} \times 8.85 \times 10^{-12} \times 4 \times 10^{4} \times 3 \times 10^{8}$
$I=53.1 W / m^{2}$
