Question
If the current is doubled, the deflection is also doubled in:
- A tangent galvanometer.
- A moving-coil galvanometer.
- Both.
- None.
Explanation:
The current and deflection dependence of a moving coil galvanometer is given by
$\text{i}=\frac{\text{k}}{\text{nAB}}\theta\Rightarrow\text{i}\propto\theta$
Therefore, if we double the current, the deflection also gets doubled.
However, in a tangent galvanometer,
$\text{i}\propto\tan\theta$; that is, there is no direct relation between $\theta$ and current.Hence, the correct option is (b).
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$\left(\right.$ Take $\left.g =10\,ms ^{-2}\right)$
