Field Intensity: a Sinusoidal Electromagnetic Wave Is Propagating in Vacuum

Essay

Field intensity: A sinusoidal electromagnetic wave is propagating in vacuum. At a given point P and at a particular time, the electric field is in the +x direction and the magnetic field is in the -y direction.
(a) What is the direction of propagation of the wave?
(b) If the intensity of the wave at point P is what is the electric field amplitude at that point? (c = 3.00 × 10⁸ m/s, μ₀ = 4π × 10^-7 T ∙ m/A, ε₀ = 8.85 × 10^-12 C²/N ∙ m²)