OK. First, we should just state the form of the 'wave equations'. These have a lot of interesting physics behind them, but for now we'll just state them!

Say the light wave travelling in the -direction, in free space. Then, say the wave is polarised, so the electric field is in the -direction. Then the only non-zero components of the fields are and :

Now, an explanation of the symbols I've used:In your question, you have been given the following information:

- is the
wavenumber(orwavevector) of the wave. It's defined by , where is the wavelength.- is the
angular frequencyof the wave. It has units of "radians per second", and relates to the 'true' frequency by .- is the speed of light.

and so you can calculate

.

( is a unit, thetesla.)

Put these into the expressions above, and ignoring the units, you get:

;

.

- - -

Your answers are written slightly diffierently: they have a minus sign, . This doesn't matter. However, I seem to have a different answer for (I don't know why!)

Also, the form used in Wikipedia has an "extra" phase factor ; I have made . You can do this just by choosing theoriginof your coordinates in the right place!