A 150μ-amp meter movement has 1000 ohm resistance, what

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A 150μ-amp meter movement has 1000 ohm resistance, what shunt resistance is required to extend the range to 750μ-amp?

1. 222 ohms
2. 225 ohms
3. 250 ohms
4. 150 ohms

Correct Option: C

Given 150μA, 1000Ω Ammeter. Let the shunt resistance R_sh is required to extend the range to 750μA as shown below in figure:

From the above figure
V = 1000 × 150 μA = R_sh × 600 μA
or

R_sh =	1000 × 150 μA
	600 μA

or
R_sh = 250Ω