Question

A galvanometer has current range of 15 mA and voltage range 750 mV. To convert this galvanometer into an ammeter of range 25 A, the required shunt is?

• A. 0.8 Ω
• B. 0.93 Ω
• C. 0.03 Ω
• D. 2 Ω

Hint:

To convert a galvanometer to an ammeter, use a shunt resistor in parallel to bypass most of the current.

Answer 1

The Correct Option is C

To convert a galvanometer into an ammeter, a shunt resistor is added in parallel. The shunt resistor can be calculated using the formula: \[ I_{\text{max}} = \frac{V_{\text{max}}}{R_{\text{total}}} \] where \( I_{\text{max}} \) is the maximum current (25 A), and \( R_{\text{total}} \) is the total resistance needed. The required shunt resistance can be derived from the voltage and current specifications.