Question:
A galvanometer is used in laboratory for detecting the null point in electrical experiments. If, on passing a current of 6 mA it produces a deflection of 2o, its figure of merit is close to :
A galvanometer is used in laboratory for detecting the null point in electrical experiments. If, on passing a current of 6 mA it produces a deflection of 2o, its figure of merit is close to :
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Figure of merit is the current required per unit deflection: \(k = I/\theta\).
Updated On: Nov 5, 2026
- \(6\times 10^{-3}\) A/div
- 666o A/div
- \(3\times 10^{-3}\) A/div
- 333o A/div
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The Correct Option is C
Solution and Explanation
Figure of merit = current needed to produce a deflection of one division = \(\frac{I}{\theta}\).
\(k = \frac{6\ \text{mA}}{2}\) = 3 mA/div = \(3\times 10^{-3}\) A/div.
Options (2) and (4) have the form of a deflection per unit current (the reciprocal quantity) with wrong units, so they are not a figure of merit.
Answer: (3) \(3\times 10^{-3}\) A/div
\(k = \frac{6\ \text{mA}}{2}\) = 3 mA/div = \(3\times 10^{-3}\) A/div.
Options (2) and (4) have the form of a deflection per unit current (the reciprocal quantity) with wrong units, so they are not a figure of merit.
Answer: (3) \(3\times 10^{-3}\) A/div
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