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Question
What would happen and why, to an electric bulb when it is connected across a supply of voltage (i) lower (ii) higher than its proper rating?
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Solution
We know, Current = Voltage/Resistance
For a given bulb, the filament would have a definite characteristic resistance. Hence
(i) When the bulb is connected to a lower voltage supply, it would draw less current than its ‘proper current’. Hence it would not glow to its full capacity.
(ii) When the bulb is connected to a higher voltage supply, it would draw more current than its ‘proper current’. Hence its filament would get heated to a temperature higher than its proper permitted limit and is, therefore, likely to melt or fuse.
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