4. A light wave is specified as following (in SI unites), Find: Ẽ =(−68 +3√5ŷ)(10¹) expil (√5x+2y)π×10² −9.42×10¹³t] . (1) The direction of electric field. (2) The scalar value of the

amplitude of the electric field. (3) The direction of propagation. (4) The wave number and wavelength. (