In a potentiometer arrangement, a cell gives a balancing point at 75 cm length of wire. This cell is now replaced by another cell of unknown emf. If the ratio of the emf's of two cells respectively is 3 : 2, the difference in the balancing length of the potentiometer wire in above two cases will be ___________ cm.
Answer (integer)
25
Solution
<p>At balancing point, we know that emf is proportional to the balancing length. i.e.,</p>
<p>emf $\propto$ balancing length</p>
<p>Now, let the emf's be 3$\varepsilon$ and 2$\varepsilon$.</p>
<p>$\Rightarrow$ 3$\varepsilon$ = k(75) ..... (1)</p>
<p>and 2$\varepsilon$ = k(l) ....... (2)</p>
<p>$\Rightarrow$ l = 50 cm</p>
<p>$\Rightarrow$ Difference is (75 $-$ 50) cm = 25 cm.</p>
About this question
Subject: Physics · Chapter: Current Electricity · Topic: EMF and Internal Resistance
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