Question

In which directions do the electric and magnetic field vectors oscillate in an electromagnetic wave propagating along the x-axis?

Answer 1

The cross product of electric and magnetic field vectors i.e. `vecE × vecB` gives the direction in which the wave travels.
It is given that wave is propagating along the x-axis. This means that electric field vector is oscillating in positive y-​direction and magnetic field vector in positive z-direction.