A radio waves electric field is given by the expression E(vector)) = E sin (kz t)

A radio wave’s electric field is given by the expression E(vector)) = E sin (kz – ωt) x (î + ĵ).
(a) Find the peak electric field.
(b) Give a unit vector in the direction of the magnetic field at a place and time where sin(kz – ωt) is positive.