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AP EAMCET · PHYSICS · Current Electricity

A galvanometer of resistance \(G \Omega\), is shunted by a resistance \(S \Omega\). To keep the main current in the circuit unchanged, the resistance to be connected in series with the galvanometer is

  1. A \(\frac{G^2}{S+G}\)
  2. B \(\frac{S}{S+G}\)
  3. C \(\frac{S^2}{S+G}\)
  4. D \(\frac{S G}{S+G}\)
Verified Solution

Answer & Solution

Correct Answer

(A) \(\frac{G^2}{S+G}\)

Step-by-step Solution

Detailed explanation

Given, galvanometer resistance, \(R_G=G\) and shunt resistance, \(R_S=S\), Let the series resistance is \(R\), so the net resistance of circuit after connected \(R\), \(R_0=R+\frac{G \times S}{G+R}\) ...(i) Since, it is given that the current should not change. So, it should be…