# How is energy dissipated in a travelling em wave

How is energy dissipated in a travelling em wave. Will there be any dissipation if it were to travel trough vaccum ?

$$E=hf$$
Where $E$ is the energy of the photon, $h$ is Plank's constant, and $f$ (or alternatively $\nu$ is the frequency of the photon.
• Welcome to Physics! Note that this site has MathJax enabled, so you can write $E=h\nu$ to get $E=h\nu$ rather than the words. – Kyle Kanos Jul 23 '15 at 21:10