An EM wave is travelling in a medium with a velocity

(a) An EM wave is travelling in a medium with a velocity $ \overrightarrow { \upsilon \quad } =\upsilon \hat { i } $ . Draw a sketch showing the
propagation of the em wave, indicating the direction of the oscillating electric and magnetic fields.
(b)How are the magnitudes of the electric and magnetic fields related to the velocity of the EM wave ?