At one point in an otherwise empty space, an electromagnetic wave has a magnetic field strength of $2.0\mathrm{\mu }\mathrm{T}$. What is the speed of this wave?

Electromagnetic waves produced by X-ray machines typically have a frequency of approximately $3.5\times10^{16}Hz$ . What is the wave number of these waves?

The magnetic field of an electromagnetic wave traveling along the z-direction is described by the wave function $B\left(z,t\right)=1.0\times10^{-3}\sin\left(kz-1.27\times10^{12}t\right)$, where k is the wave number. Write the complete wave function for the electric field of this wave.

Electromagnetic waves produced by X-ray machines typically have a frequency of approximately $3.5\times10^{16}Hz$ . What is the wave number of these waves?