GCSE PHYSICS - What is the Energy Efficiency of Different Types of Lighting? - Energy Saving Bulb - LED - CFL - GLS

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Energy - What are the Different Types of Lighting?

There are many different forms of lighting. These include

1. A traditional filament lamp
called a GLS (general lighting service) lamp.

2. A more modern energy saving bulb
called a compact fluorescent lamp (CFL)

3. A light emitting diode (LED).

How Energy Efficient are the Different Types of Lighting?

A filament lamp might be supplied with 6000J in one minute
and produce 1200J of light.
The efficiency is (1200 ÷ 6000) x 100
= 20 %.

An energy saving bulb is a small fluorescent lighting tube
which may have a spiral or be folded four times
and sometimes has a round glass bulb around it.
An energy saving bulb might be supplied with 1500J
in one minute and produce 1200J of light.
The efficiency is (1200 ÷ 1500) x 100
= 80 %.
The wasted energy for both bulbs is in the form of heat.

The energy saving bulb (CFL) is more expensive to buy
than the GLS filament lamp but more cost-effective to use.

An alternative light source is the LED (light emitting diode).
These are being used more as time goes by.
LED lights are more expensive to buy but use less current
and last much longer, 10 to 20 years is not uncommon.
See the circuit symbol for a LED.
The efficiency of a LED and a CFL are similar.

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