Final answer:
The amplitude of the magnetic field oscillations in an electromagnetic wave can be found using the relationship between the electric field and magnetic field. In this case, the amplitude of the magnetic field is 3.4 x 10^(-7) T.
Step-by-step explanation:
The amplitude of the magnetic field oscillations in an electromagnetic wave can be found by using the relationship between the electric field and magnetic field in an electromagnetic wave. The amplitude of the magnetic field (B) is related to the amplitude of the electric field (E) by the equation B = E/c, where c is the speed of light in a vacuum. In this case, the amplitude of the electric field given is Ey = 102 N/C. Therefore, the amplitude of the magnetic field would be B = (102 N/C) / (3 x 10^8 m/s) = 3.4 x 10^(-7) T.