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Physics · 2023 · 2 marks
CBSE 2023 · Region 4 · Set 1 · Q20
Write two differences between the emf and terminal potential difference of a cell. What is the most important precaution that one should take while…
Write two differences between the emf and terminal potential difference of a cell. What is the most important precaution that one should take while drawing current from a cell ?
Marking-scheme solution
Two differences
1. The potential difference across the electrodes in open circuit is e.m.f. ( \(\displaystyle \varepsilon\) ) and in closed circuit is terminal potential difference (V).
2. V depends on r and \(\displaystyle \varepsilon\) is independent of r.
Precaution-1. Some external resistance should be connected to cell in series.
2. Short circuiting should be avoided.
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