Inventing a viable electric light was hard, I mean, this is the typical incandescent design, which just involves passing electric current through a material making it so hot that it glows, less than 5% of the electrical energy comes out as light.

发明一种可行的电灯是很困难的, 我的意思是, 这是典型的白炽灯设计, 只需让电流通过某种材料，使其变得非常热，从而发光，只有不到5%的电能以光的形式出现。