A current of $2×10^{-5} A$ produces 25 division deflection in a galvanometer. The resistance of the galvanometer coil is 4 Ω. The figure of merit of galvanometer is:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → $8×10^{-7}$ ampere/division
Figure of merit of a galvanometer is defined as the current required to produce a deflection of one division on a scale.
Figure of merit = $\frac{Current(I)}{Deflection(d)}$
where,
I, Current = $2×10^{-5}A$ [given]
d = 25 divisions [given]
Figure of merit = $\frac{I}{d}=\frac{2×10^{-5}}{25}$
$=8×10^{-7}A/division$