- Home
- Standard 12
- Physics
8.Electromagnetic waves
medium
The electric field in an electromagnetic wave is given by $E =56.5 \sin \omega( t - x / c ) \;NC ^{-1}$. Find the intensity of the wave if it is propagating along $x-$axis in the free space. (Given $\left.\varepsilon_{0}=8.85 \times 10^{-12} \;C ^{2} N ^{-1} m ^{-2}\right)$
A
$5.65 \;Wm ^{-2}$
B
$4.24 \;Wm ^{-2}$
C
$1.9 \times 10^{-7} \;Wm ^{-2}$
D
$56.5 \;Wm ^{-2}$
(JEE MAIN-2022)
Solution
$I =\frac{1}{2} \varepsilon_{0} E _{0}^{2} c$
$I =\frac{1}{2} \times\left(8.85 \times 10^{-12}\right)(56.5)^{2} \times\left(3 \times 10^{8}\right)$
$=4.24 Wm ^{-2} .$
Standard 12
Physics
