Current Electricity - Result Question 97
102. The resistances in the two arms of the meter bridge are $5 \Omega$ and $R \Omega$, respectively. When the resistance $R$ is shunted with an equal resistance, the new balance point is at $1.6 l_1$. The resistance ’ $R$ ’ is :
[2014]
(a) $10 \Omega$
(b) $15 \Omega$
(c) $20 \Omega$
(d) $25 \Omega$
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Answer:
Correct Answer: 102. (b)
Solution:
- (b) This is a balanced wheatstone bridge condition,
$\frac{5}{R}=\frac{\ell_1}{100-\ell_1}$ and $\frac{5}{R / 2}=\frac{1.6 \ell_1}{100-1.6 \ell_1}$
$\Rightarrow R=15 \Omega$
