Question

A milli voltmeter of 25 milli volt range is to be converted into an ammeter of 25 ampere range. The value (in ohms) of necessary shunt will be

• A. 0.001
• B. 0.005
• C. 0.1
• D. 0.5

Hint:

To convert a voltmeter to an ammeter, a shunt resistor is connected in parallel, calculated based on the range of the ammeter and voltmeter.

Answer 1

The Correct Option is A

Step 1: Use the shunt resistor formula.
The shunt resistor \( R_s \) is given by: \[ R_s = \frac{V}{I} - R_{\text{mv}} \] where \( V \) is the voltage range of the ammeter, \( I \) is the current range, and \( R_{\text{mv}} \) is the resistance of the voltmeter.
Step 2: Apply the formula.
Substituting the values: \[ R_s = \frac{25}{25} - 0.025 = 0.001 \, \Omega \]
Final Answer: \[ \boxed{0.001 \, \Omega} \]