Paheli set up an experiment using liquid A in the beaker as shown in Fig. 14.4. She observed that the bulb glows. Then she replaced the liquid A by another liquid B. This time the bulb did not glow. Boojho suggested replacing the bulb by an LED. They observed that the LED glows. Explain.
When experiment is performed using liquid A the bulb glows because A is a good conductor of electricity.
But when liquid A is replaced by liquid B, bulb does not glow because the current is not sufficient to heat the filament. This is because liquid B is a poor conductor of electricity.
In the place of electric bulb, LED can always be used because LED glows even when a weak current flows through it.
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