The magnitude of the electric and magnetic fields in an electromagnetic wave are related as:

$B_0=E_0/C$

The correct answer is Option (2) → $B_0=E_0/C$

In an electromagnetic wave, the electric field $E$ and the magnetic field $B$ are related by:

$\frac{E}{B} = c$

where $c$ is the speed of light in vacuum.

Thus,

$E = cB$

or equivalently,

$B = \frac{E}{c}$

Relation: $E = cB$