Resistance in two gaps of a meter bridge are 10, ohm and 30, ohm respectively. If resistances are in

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3.Current Electricity

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Resistance in the two gaps of a meter bridge are $10\, ohm$ and $30\, ohm$ respectively. If the resistances are interchanged the balance point shifts by.............. $cm$

$33.3$

$66.67$

$25$

$50$

Solution

(d)$S = \left( {\frac{{100 – l}}{l}} \right).R$
Initially, $30 = \left( {\frac{{100 – l}}{l}} \right) \times 10 \Rightarrow l = 25\,cm$
Finally, $10 = \left( {\frac{{100 – l}}{l}} \right) \times 30 \Rightarrow l = 75\,cm$
So, shift = $50\,cm.$

Standard 12

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