Moving Charges and Magnetism - Result Question 77

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79. 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 [2011M]

======= ####79. 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 [2011M]

3e0f7ab6f6a50373c3f2dbda6ca2533482a77bed:content/english/neet-pyq-chapterwise/physics/moving-charges-and-magnetism/moving-charges-and-magnetism—result-question-77.md (a) $\frac{S^{2}}{(S+G)}$

(b) $\frac{SG}{(S+G)}$

(c) $\frac{G^{2}}{(S+G)}$

(d) $\frac{G}{(S+G)}$

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Answer:

Correct Answer: 79. (c)

Solution:

  1. (c) To keep the main current in the circuit unchanged, the resistance of the galvanometer should be equal to the net resistance.

$\therefore G=(\frac{GS}{G+S})+S^{\prime}$

$\Rightarrow G-\frac{GS}{G+S}=S^{\prime}$