How much electricity does halogen linear tube (about 18cm with 500w) use? I am scared to turn the light on.?

-In broad terms, in 2011 the average cost of electricity in the US was 11.9 cents per Kwh, 500 watts is 1/2 a Kw per hour, so it will cost 6 cents an hour, if you live in an average place.A 500 watt bulb will usually use 500 watts of power
500 watts. About 4 amps at 120vac.