Question

An ammeter reads up to 1 A. Its internal resistance is 0.81 \( \Omega \). To increase the range to 10 A, the value of the required shunt is:

• A. 0.09 \( \Omega \)
• B. 0.39 \( \Omega \)
• C. 0.99 \( \Omega \)
• D. 0.09 \( \Omega \)

Hint:

The shunt resistance is used to extend the range of an ammeter by bypassing a portion of the current.

Answer 1

The Correct Option is A

Step 1: Use the formula for shunt resistance.
The shunt resistance is given by: \[ R_s = \frac{R}{n - 1} \] where \( R \) is the internal resistance of the ammeter, and \( n \) is the multiplication factor (ratio of the new range to the original range).
Step 2: Calculation.
Substituting the values: \[ R_s = \frac{0.81}{10 - 1} = 0.09 \, \Omega \]
Final Answer: \[ \boxed{0.09 \, \Omega} \]