A galvanometer having coil resistance 10 Ω shows a full scale deflection for a current of 3 mA. For it to measure a current of 8 A, the value of the shunt should be: (a) 3.75 × 10⁻³ Ω (b) 3 × 10⁻³ Ω (c) 4.85 × 10⁻³ Ω (d) 2.75 × 10⁻³ Ω

Answer: (a). S = (Ig G)/(I - Ig) S = 3 × 10⁻³ × 108 - 0.003 = (0.03)/(7.997) ≈ 3.75 × 10⁻³ Ω So the answer is (a) 3.75 × 10⁻³ Ω.

A galvanometer having coil resistance 10 Ω shows a full scale… | JEE Main 2024 (29 Jan, Shift 1)

Q48JEE Main 2024 · 29 JAN · SHIFT 1Easy

Kirchhoff's Laws & Measuring Instruments

A galvanometer having coil resistance $10\ \Omega$ shows a full scale deflection for a current of $3\text{ mA}$ . For it to measure a current of $8\text{ A}$ , the value of the shunt should be:

Show answer and solution

Answer: (a)

$S = \frac{I_g G}{I - I_g}$
$S = \frac{3 \times 10^{-3} \times 10}{8 - 0.003} = \frac{0.03}{7.997} \approx 3.75 \times 10^{-3}\ \Omega$
So the answer is (a) $3.75 \times 10^{-3}\ \Omega$ .

Report a mistake

Kirchhoff's Laws & Measuring Instruments question from JEE Main 2024 (29 Jan, Shift 1)

More questions on Kirchhoff's Laws & Measuring Instruments