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An $EM$ wave propagating in $x$-direction has a wavelength of $8\,mm$. The electric field vibrating $y$ direction has maximum magnitude of $60\,Vm ^{-1}$. Choose the correct equations for electric and magnetic fields if the $EM$ wave is propagating in vacuum
$E_{y}=60 \sin \left[\frac{\pi}{4} \times 10^{3}\left( x -3 \times 10^{8} t \right)\right] \hat{ j }\,Vm ^{-1}$
$B _{z}=2 \sin \left[\frac{\pi}{4} \times 10^{3}\left( x -3 \times 10^{8} t \right)\right] \hat{ k }\,T$
$E_{y}=60 \sin \left[\frac{\pi}{4} \times 10^{3}\left( x -3 \times 10^{8} t \right)\right] \hat{ j }\,Vm ^{-1}$
$B _{z}=2 \times 10^{-7} \sin \left[\frac{\pi}{4} \times 10^{3}\left( x -3 \times 10^{8} t \right)\right] \hat{ k }\,T$
$E _{y}=2 \times 10^{-7} \sin \left[\frac{\pi}{4} \times 10^{3}\left( x -3 \times 10^{8} t \right)\right] \hat{ j }\,Vm ^{-1}$
$B _{z}=60 \sin \left[\frac{\pi}{4} \times 10^{3}\left( x -3 \times 10^{8} t \right)\right] \hat{ k }\, T$
$E _{ y }=2 \times 10^{-7} \sin \left[\frac{\pi}{4} \times 10^{4}\left( x -4 \times 10^{8} t \right)\right] \hat{ j }\,Vm ^{-1}$
$B _{z}=60 \sin \left[\frac{\pi}{4} \times 10^{4}\left( x -4 \times 10^{8} t \right)\right] \hat{ k } \,T$
Solution
$B _{0}=\frac{ E _{0}}{ c }=\frac{60}{3 \times 10^{8}}=2 \times 10^{-7}\,T$
$\widehat{ E } \times \widehat{ B }$ must be direction of propagation
So, $\widehat{B} \rightarrow z$-axis
$k =\frac{2 \pi}{\lambda}=\frac{\pi}{4} \times 10^{3}\,m ^{-1}$
$E _{ y }=60 \sin \left[\frac{\pi}{4} \times 10^{3}\left( x -3 \times 10^{8} t \right)\right] \hat{ j } Vm ^{-1}$
$B _{z}=2 \times 10^{-7} \sin \left[\frac{\pi}{4} \times 10^{3}\left( x -3 \times 10^{8} t \right)\right] \hat{ k } T$
