Graphite is an electric conductor, consequently, useful in such applications as arc lamp electrodes. It can conduct electricity due to the vast electron delocalization within the carbon layers (a phenomenon called aromaticity). These valence electrons are free to move, so are able to conduct electricity.
A “normal” incandescent bulb costs about 0.75cents per hour, and LEDs or CFLs cost only one-sixth of that – so leaving the lights on (either overnight or while you’re at work for the day, say both are about 8 hours) costs you roughly 6 cents for a normal light and a bit over 1 cent for modern bulbs.
The name Greenland comes from Scandinavian settlers. In the Norse sagas, it is said that Erik the Red was exiled from Iceland for murder. He set out in ships to find land rumoured to be to the northwest. After settling there, he named the land Grfnland (Greenland), possibly to attract more people to settle there.