Electromagnetic Waves

The direction of propagation of the electromagnetic wave is along $+z$

The speed of the electromagnetic wave inside the medium is $10^8 \mathrm{~ms}^{-1}$

The wavelength of the electromagnetic wave inside the medium is 300 m

The magnetic field is given by the relation $B_y=\frac{B_0}{v} \sin \left(k z-2 \pi \times 10^6 t\right)$ where $v$ is the speed of the electromagnetic wave inside the medium