Compare the function of incandescent and fluorescent light bulbs and how this affects their efficiency.

Incandescent and fluorescent light bulbs function differently and this greatly affects their efficiency.

1. Function:

   • Incandescent Bulbs: These bulbs produce light by heating a metal filament wire to a high temperature until it glows. The heat is generated by electric current passing through the filament.
   • Fluorescent Bulbs: These bulbs produce light by passing an electric current through a tube containing argon and a small amount of mercury vapor. This generates invisible ultraviolet light that excites a fluorescent coating (called phosphor) on the inside of the tube, which then emits visible light.

2. Efficiency:

   • Incandescent Bulbs: These bulbs are less energy efficient. A lot of the energy is wasted in the form of heat. Only about 10% of the energy used by an incandescent light bulb produces light, the rest is turned into heat.
   • Fluorescent Bulbs: These bulbs are more energy efficient. They use only about 25%-35% of the energy used by incandescent bulbs to produce the same amount of light. They also last about 10 times longer.

In conclusion, while incandescent bulbs are cheaper upfront, fluorescent bulbs are more cost-effective in the long run due to their energy efficiency and longer lifespan.