The energy densities associated with the electric field E and magnetic field B of an electromagnetic wave in free space are given respectively by (where ε0 is the permittivity of free space and μ0 is the permeability of free space):

Match List I (Electromagnetic wave) with List II (Production method): List I: A. Microwave B. Visible light C. Gamma rays D. Infrared rays List II: I. Electrons in atoms emit light when moving from a higher to a lower energy level II. Radioactive decay of the nucleus III. Vibration of atoms and molecules IV. Klystron valve or magnetron valve Choose the correct matching:

For a plane electromagnetic wave propagating along the +x-direction, which of the following combinations gives the correct possible directions for the electric field (E) and magnetic field (B) respectively?