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MHT CET · Physics · Current Electricity

A galvanometer of resistance \(50 \Omega\) is converted to an ammeter. After shunting, the effective resistance of ammeter is \(2.5 \Omega\). The value of shunt is

  1. A \(\frac{100}{19} \Omega\)
  2. B \(\frac{50}{19} \Omega\)
  3. C \(\frac{25}{19} \Omega\)
  4. D \(\frac{75}{19} \Omega\)
Verified Solution

Answer & Solution

Correct Answer

(B) \(\frac{50}{19} \Omega\)

Step-by-step Solution

Detailed explanation

The resistance of the galvanometer and the shunt are in parallel. Their equivalent resistance is given by
\(
\begin{aligned}
& \frac{1}{\mathrm{R}}=\frac{1}{\mathrm{G}}+\frac{1}{\mathrm{~S}} \\
& \therefore \frac{1}{\mathrm{~S}}=\frac{1}{2.5}-\frac{1}{50}=\frac{19}{50}
\end{aligned}
\)
Or \(\mathrm{S}=\frac{50}{19} \Omega\)