A galvanometer having coil resistance 10 Ω shows a full scale deflection for a current of 3 mA . For it to…

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:
  1. 3×10-3Ω
  2. 4.85×10-3Ω
  3. 3.75×10-3Ω
  4. 2.75×10-3Ω

Solution

Given G=10 Ω, Ig=3 mA and I=8 A.

Let's consider the following figure:

From the figure, we have

IgG=I-IgS⇒S=IgGI-Ig⇒S=3×10-3108-0.003=3.75×10-3 Ω

Asked in: JEE Main 2024 (29 Jan Shift 1)

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