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

G1 Physics · Accepted Answer

Given, G = 10 Ω I(g) = 3 mA = 3 × 10⁻³ A I = 8 A For conversion of galvanometer into ammeter, I(g) G = (I - I(g))S Therefore, S = I(g) G /(I - I(g)) = (3 × 10⁻³ × 10)/(8 - 0.003) ≈ 3.75 × 10⁻³ Ω