Your eye doesnt notice the ons and offs but it does notice the overall effect. Add up the wattage of each light on that switch and you have your answer.
Dimmer Wikipedia
What does a dimmer switch do. Most dimmers are designed to fit a standard wall box opening which makes it easy to replace the switch for any incandescent or halogen light with a dimmer. If you have 4 lights that are 50w each youll need a 200w dimmer or bigger. In this article well look inside one of these everyday devices to find out how it controls lamp fixtures. A dimming or less intense light brightness. Enter the dimmer switch a handy electrical component that lets you adjust light levels from nearly dark to fully lit by simply turning a knob or sliding a lever. To work out the load on your dimmer and therefore what dimmer wattage you need to order you will need to make a simple calculation.
By changing the voltage waveform applied to the lamp it is possible to lower the intensity of the light output. The use of a dimmer switch has multiple advantages. As it turns out the inner workings are pretty cool and surprising. Instead of merely turning lights on or off get a wide range of light by installing a dimmer switch. A dimmers is a device connected to a light fixture and used to lower the brightness of light. Also with a dimmer switch its easy to adjust the ambiance of the room to suit your preferences at any time.
The calculation couldnt be simpler. Essentially the technology inside the dimmer switch controls the flow of electricity to your lights by turning it on and off many many times per second. Dimmer switches have electronic components that produce heat and will make the cover plate warm however they should never get hot. Through the use of a dimmer you can reduce the amount of energy youre using thus saving money on your electric bill.