## College Physics (4th Edition)

Although the expression $E = cB$ can be a useful ratio, it can not be used to compare the magnitude of the electric field to the magnitude of the magnetic field in any meaningful way because they are measured in different units.
The electric field $E$ is measured in units of $N/C$. The magnetic field $B$ is measured in units of Tesla. Although the expression $E = cB$ can be a useful ratio, it can not be used to compare the magnitude of the electric field to the magnitude of the magnetic field in any meaningful way because they are measured in different units. It would be like claiming that a mass of $12~kg$ is bigger than a distance of $4~km$. Although the number $12$ is bigger than the number $4$, it is not meaningful to compare a mass with a distance. Similarly, it is not meaningful to compare the magnitude of an electric field to the magnitude of a magnetic field.