Photocells
How does the color of light affect the electrical output of a photocell (solar cell)? What about the distance of the bulb from the cell, or the the type of light bulb? Does the heat given off by incandescent, compact fluorescent, or LED bulbs provide a clue about how efficient these bulbs are? How much electricity (i.e. how powerful a light source) does it take to power motors, pumps, buzzers and other devices?