With the gradual phasing out of incandescent light bulbs, you'll see more compact fluorescent lamps (CFLs) on the market, along with light-emitting diode lamps (LEDs). Also called compact fluorescent bulbs or energy-saving bulbs, CFLs contain trace amounts of mercury and must be disposed of carefully at hazardous waste or recycling centers. CFLs fit standard light bulb sockets but use less electricity than incandescent bulbs. Though CFLs can last for years, their electrodes and ballasts will eventually fail.
Flip the switch and wait a few seconds. If the fluorescent bulb fails to come on, turn the switch off. Try another light. If it comes on, you've ruled out a power failure in your area.
Turn the fluorescent bulb clockwise to see if it's firmly seated in the socket. If it doesn't turn, you've ruled out a loose bulb.
Check your circuit breaker box and confirm that the corresponding breaker is firmly in the "on" position. If it isn't, flip the breaker back to the "on" position. If it is, you've ruled out a problem in the circuit.
Change out the fluorescent bulb with a new one. Turn the switch on. If the light comes on after a few seconds, you'll know the original bulb burned out.