Current Electricity 4 Question 12
12. In a potentiometer experiment, it is found that no current passes through the galvanometer when the terminals of the cell are connected across $52 cm$ of the potentiometer wire. If the cell is shunted by a resistance of $5 \Omega$, a balance is found when the cell is connected across $40 cm$ of the wire. Find the internal resistance of the cell.
(2018 Main)
(a) $1 \Omega$
(b) $2 \Omega$
(c) $1.5 \Omega$
(d) $2.5 \Omega$
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Solution:
- Using formula, $r=R \frac{l _1}{l _2}-1=5 \frac{52}{40}-1=5 \times \frac{12}{40}=1.5 \Omega$
