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JEE Main 2016 · Kirchhoff's Laws & Measuring Instruments

Kirchhoff's Laws & Measuring Instruments question from JEE Main 2016

Q175JEE Main 2016Easy

Kirchhoff's Laws & Measuring Instruments

A galvanometer having a coil resistance of 100 Ω100\ \Omega gives a full scale deflection, when a currect of 1 mA1\text{ mA} is passed through it. The value of the resistance, which can convert this galvanometer into ammeter giving a full scale deflection for a current of 10 A,10\text{ A}, is:

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Answer: (c)

  1. S=IgGI−IgS = \frac{I_g G}{I - I_g}
  2. S=10−3×10010−0.001≈0.110=0.01 ΩS = \frac{10^{-3} \times 100}{10 - 0.001} \approx \frac{0.1}{10} = 0.01\ \Omega
  3. So the answer is (c) 0.01 Ω0.01\ \Omega.
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