A plane EM wave is propagating along \( x \) direction. It has a wavelength of \( 4 \, \text{mm} \). If electric field is in \( y \) direction with the maximum magnitude of \( 60 \, \text{V m}^{-1} \), the equation for magnetic field is:
\( B_z = 2 \times 10^{-7} \sin \!\left[ \frac{\pi}{2} \!\left( x - 3 \times 10^{8} t \right) \right] \hat{k} \, \text{T} \)
\( B_z = 2 \times 10^{-7} \sin \!\left[ \frac{\pi}{2} \times 10^{3} \!\left( x - 3 \times 10^{8} t \right) \right] \hat{k} \, \text{T} \)
\( B_z = 60 \sin \!\left[ \frac{\pi}{2} \!\left( x - 3 \times 10^{8} t \right) \right] \hat{i} \, \text{T} \)
\( B_z = 60 \sin \!\left[ \frac{\pi}{2} \!\left( x - 3 \times 10^{8} t \right) \right] \hat{k} \, \text{T} \)
