Question 9 โ€” Which LED will glow - Questions at the end of the chapter - Chapter 4 Class 8 - Electricity: Magnetic & Heating Effects(Curiosity)

Last updated at June 5, 2026 by

Q 9
Question

In Fig. 4.11, beaker (a) has copper and iron in lemon juice, and beaker (b) has copper and iron in pure water. In which case will the LED glow when the switch is closed?

๐Ÿ”— Concept: 4.3.1 Voltaic Cell

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The LED glows only in beaker (a), with lemon juice.

Explanation

  • Lemon juice is an electrolyte, so it helps make current.
  • So the cell in beaker (a) works and the LED glows.
  • Pure water is not a good electrolyte, so beaker (b) makes almost no current.
  • So the LED in beaker (b) does not glow.
An electrolyte like lemon juice is needed to make current.
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