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NEET 2011 (AIPMT, Mains) · Moving Coil Galvanometer, Ammeter & Voltmeter

Moving Coil Galvanometer, Ammeter & Voltmeter question from NEET 2011 (AIPMT, Mains)

Q25NEET 2011 · AIPMT · MAINSMedium

Moving Coil Galvanometer, Ammeter & Voltmeter

A galvanometer of resistance, G, is shunted by a resistance S ohm. To keep the main current in the circuit unchanged, the resistance to be put in series with the galvanometer is

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Answer: (d)

  1. With the shunt the resistance becomes GSG+S\frac{GS}{G+S}; to keep the main current unchanged the total must stay GG.
  2. R+GSG+S=GR + \frac{GS}{G+S} = G
  3. R=G−GSG+S=G2G+SR = G - \frac{GS}{G+S} = \frac{G^2}{G+S}
  4. So the answer is (d) G2S+G\frac{G^2}{S+G}.
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