Consider the following statements regarding electromagnetic waves
(i) In free space, its speed,  $c=\frac{1}{\sqrt{{\mu }_0{\in }_0}}=3\times {10}^{8}m/s$
(ii) In medium, its speed,  $v=\frac{1}{\sqrt{\mu \in }}$
(iii) The energy crossing unit area per unit time perpendicular to the direction of propagation of EM wave is called intensity and is equal to  $I=\frac{1}{2}{\in }_0{E}^{2}c=\frac{B^2}{2{\mu }_0}c$
(iv) In electro magnetic wave electric and magnetic fields are of different strength but energyof the light is equally shared among the two fields
How many statements are correct in the above ?