The electric field component of a uniform plane electromagnetic wave propagating in the $Y$-direction in a lossless medium will satisfy the equation.
- $\frac{\partial^2 E_y}{\partial y^2}=\mu \in \frac{\partial^2 E_y}{\partial t^2}$
- $\frac{\partial^2 E_y}{\partial x^2}=\mu \in \frac{\partial^2 E_y}{\partial t^2}$
- $\frac{\partial^2 E_x}{\partial y^2}=\mu \in \frac{\partial^2 E_x}{\partial t^2}$
- $\frac{\sqrt{E_x^2+E_z^2}}{\sqrt{H_x^2+H_z^2}}=\sqrt{\frac{\mu}{\epsilon}}$