An array is a special variable, which can hold more than one value at a time. If you have a list of items (a list of car names, for example), storing the cars in single variables could look like this:
milliamps or watt/volt. The SI base unit for electric current is the ampere. 1 ampere is equal to 1000 milliamps, or 1 watt/volt. Note that rounding errors may occur, so always check the results. Use this page to learn how to convert between milliamperes and watts/volt. Type in your own numbers in the form to convert the units!
Stimpy, the power rating tells you the rate at which the device consumes energy. So yes, a 60-Watt bulb will consume 60W*h or 0.06kWh of electricity in one hour. Watt-hours measure energy consumption. There is a simple little page here that shows some calculations.