For designing a voltmeter of range 50 V and an ammeter of range 10 mA using a galvanometer which has a coil of resistance 54 Ω showing a full scale deflection for 1 mA as in figure. (A) for voltmeter R ≈ 50 kΩ (B) for ammeter r ≈ 0.2 Ω (C) for ammeter r = 6 Ω (D) for voltmeter R ≈ 5 kΩ (E) for voltmeter R ≈ 500 Ω Choose the correct answer from the options given below: (a) (A) and (C) (b) (A) and (B) (c) (C) and (E) (d) (C) and (D)

Answer: (a). Voltmeter: series R = V/Ig - G = 5010⁻³ - 54 = 49946 Ω ≈ 50 kΩ, so (A) is true. Ammeter: shunt r = (Ig G)/(I - Ig) = (1 × 54)/(10 - 1) = 6 Ω, so (C) is true. (B), (D), (E) do not match these values. So the answer is (a) (A) and (C).

For designing a voltmeter of range 50 V and an ammeter of range 10 mA… | JEE Main 2023 (15 Apr, Shift 1)

Q96JEE Main 2023 · 15 APR · SHIFT 1Medium

Kirchhoff's Laws & Measuring Instruments

For designing a voltmeter of range $50\text{ V}$ and an ammeter of range $10\text{ mA}$ using a galvanometer which has a coil of resistance $54\ \Omega$ showing a full scale deflection for $1\text{ mA}$ as in figure.

(A) for voltmeter $R \approx 50\text{ k}\Omega$

(B) for ammeter $r \approx 0.2\ \Omega$

(D) for voltmeter $R \approx 5\text{ k}\Omega$

(E) for voltmeter $R \approx 500\ \Omega$

Choose the correct answer from the options given below:

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Answer: (a)

Voltmeter: series $R = \frac{V}{I_g} - G = \frac{50}{10^{-3}} - 54 = 49946\ \Omega \approx 50\text{ k}\Omega$ , so (A) is true.
Ammeter: shunt $r = \frac{I_g G}{I - I_g} = \frac{1 \times 54}{10 - 1} = 6\ \Omega$ , so (C) is true.
(B), (D), (E) do not match these values.
So the answer is (a) (A) and (C).

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Kirchhoff's Laws & Measuring Instruments question from JEE Main 2023 (15 Apr, Shift 1)

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