Answers

2016-03-31T08:28:01+05:30

Yes! Glowing of bulb is a physical change.When an electric current is passed through the filament of a bulb, the filament starts glowing and the glow stops as soon as the current is cut off. The chemical composition of the tungsten filament does not change on application of current.

Burning of candle is both a physical change as well as a chemical change. Candle is made up of a solid block of wax with a wick embedded in it.

1) Physical Change

When candle is lit, the heat of the flame melts the solid wax to liquid wax. This signifies a physical change from solid state to liquid state.

2) Chemical Change

The wax acts as a fuel when we light the candle and is basically a chemical substance called carbon. The carbon combines with oxygen to form another chemical substance called carbon dioxide. Also the unburnt carbon is deposited as black substance called soot. This signifies a chemical change.

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