Measuring Devices ( Galvanometer, Voltmeter and Ammeter & Meter Bridge ): Practice Problem & Solution

Solution Explained:

To solve this problem, we apply the core principles of Measuring Devices ( Galvanometer, Voltmeter and Ammeter & Meter Bridge ). Understanding the underlying formula is key to arriving at the correct answer below:

An ammeter is designed to measure larger currents than a milliammeter. To achieve a larger current range with the same galvanometer, a smaller shunt resistance is required to bypass a greater portion of the total current. A smaller shunt resistance results in a lower overall resistance for the ammeter. Thus, Assertion (A) is true. Reason (R) states the shunt resistance for an ammeter is more than a milliammeter, which is false; it must be less.