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Why do light bulbs blow once they're switched on?
Why do light-bulbs blow when you turn them on?
Name: Andy, Waterford, Ireland
Qualification: He's an electronics engineer
Answer: A standard light bulb consists of a little coil of wire inside the glass bulb. When switched on, the electric current runs through the coil and heat up and glows. Because there’s no air in the bulb it gets warmer. When heated, it expands. If there’s a problem with it, the movement when the metal expands causes the fracture.