The brightness of an electric light is measured in lumens. A 60 watt incandescent light bulb has a brightness of 800 lumens. The efficiency of an electric light is measured in lumens per watt. Incandescent light bulbs have an efficiency
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Ordinary incandescent light bulbs have been around for a hundred years. In fact they’re still around. They were never made illegal. They are cheap, costing around 70p, and a lot of budget shops still sell them. What are the problems