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MHT CET 2023 (9 May, Shift 2) · Kirchhoff's Laws & Measuring Instruments

Kirchhoff's Laws & Measuring Instruments question from MHT CET 2023 (9 May, Shift 2)

Q95MHT CET 2023 · 9 MAY · SHIFT 2Medium

Kirchhoff's Laws & Measuring Instruments

A galvanometer of resistance 20 Ω20\ \Omega gives a deflection of 5 divisions when 1 mA1\text{ mA} current flows through it. The galvanometer scale has 50 divisions. To convert the galvanometer into a voltmeter of range 25 volt, we should connect a resistance of

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Answer: (b)

  1. 5 divisions per mA, so full scale (50 divisions) Ig=10 mA=0.01 AI_g = 10\text{ mA} = 0.01\text{ A}.
  2. Series resistance R=VIg−G=250.01−20R = \dfrac{V}{I_g} - G = \dfrac{25}{0.01} - 20
  3. R=2500−20=2480 ΩR = 2500 - 20 = 2480\ \Omega in series
  4. So the answer is (b).
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