Why Does My Incandescent Light Hum?
Incandescent bulbs may hum when used with a dimmer switch. When a dimmer is used, the bulb is actually turned on/off faster than the human eye can register. This constant on/off can cause vibration of the filament within the bulb. Thus a slight humming sound. A quick fix would be to replace the bulb with a rough service version or to upgrade your dimmer switch to improve current management and reduce/eliminate the vibration.
For more information about incandescent light bulbs, contact Pacific Lamp.