Question

An ammeter reads upto $1$ ampere. Its internal resistance is $0.81\Omega$. To increase the range to $10A$ the value of the required shunt is

• A. $0.03\Omega$
• B. $0.3\Omega$
• C. $0.9\Omega$
• D. $0.09\Omega$

Answer 1

Answer: (D)

$0.09\Omega$

Given : $I_g=1$ A $R_g=0.81\Omega$ $I=10$ A

Shunt resistance $R_s=\frac{I_g{R}_g}{I-I_g}=\frac{1\times 0.81}{10-1}=0.09\Omega$