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MHT CET · Physics · Current Electricity

In an ammeter, \(4 \%\) of the main current is. passing through the galvanometer, If shunt resistance is \(5 \Omega\), then resistance of galvanometer will be

  1. A \(60 \Omega\)
  2. B \(120 \Omega\)
  3. C \(240 \Omega\)
  4. D \(480 \Omega\)
Verified Solution

Answer & Solution

Correct Answer

(B) \(120 \Omega\)

Step-by-step Solution

Detailed explanation

Shunt \(S=\frac{\mathrm{I}_{\mathrm{g}} \mathrm{G}}{\mathrm{I}-\mathrm{I}_{\mathrm{g}}}\)

On substituting the given values, we get,
\(\begin{aligned}
\therefore \quad & 5=\frac{\left(\frac{4}{100} \mathrm{I} \times \mathrm{G}\right)}{\mathrm{I}-\frac{4}{100} \mathrm{I}}=\frac{4 \mathrm{G}}{96} \\
& \Rightarrow \mathrm{G}=\frac{96 \times 5}{4}=120 \Omega
\end{aligned}\)