New full scale deflection of an ammeter

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Bolter
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Homework Statement
Calculate the new full scale deflection of the ammeter
Relevant Equations
Rs = iRc/I-i
Question:
Text problem: A moving coil ammeter gives full scale deflection for current i = 250 mA, coil resistance Rc = 3.6 ohms. Shunt resistor Rsh = 0.2 ohms is used. Asks for the new full scale deflection current.


My attempt:

Handwritten derivation: Rs = iRc/(I-i) rearranged to I = i(Rc+Rs)/Rs, then I = 250x10^-3(8.6+0.2)/0.2 = 4.75 A.


Does 4.75 amps for the full scale deflection seem okay?

Thanks for any help!
 

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