0 Members and 1 Guest are viewing this topic.
Lets say that I have a 60 watt globe in my room. 1) When I switch on that light and keep it on for an hour I will use 60 watt of electricity, or does the light use extra electricity to switch on? What will the total electricity consumption be for that hour?
2) If I switch on the light and keep it on for 3 minutes, switch it ofwhen I leave the room, come back and switch it on, lets say ten times. What will my total consumption be in that 30 minutes.
What I actually would like to know is, is it better to leave a light burning or switch it on and of when needed..
... The electrical resistance of the filament is proportional to its temperature, so for a fraction of a second immediately after it is switched on the power consumption will be greater than 60W because the electrical resistance of the room-temperature filament is lower than when it is white-hot. There will be a momentary current spike when the incandescent bulb is switched on from cold.
Actually it might be a step too far to say the "electrical resistance of the filament is proportional to its temperature".The resistance will certainly go up with increasing temperature, but over the range we're considering, I wonder how close it really is to a strict proportionality...?