Which one of the following electrical meter has the smallest resistance ?

Options

A. Ammeter
B. Milliammeter
C. Galvanometer
D. Voltmeter

Answer

To determine which electrical meter has the smallest resistance among the given options, we will analyze each type of meter and their construction.

### Step-by-Step Solution:

1. **Understanding the Types of Meters**:
- The question presents different types of electrical meters: ammeter, voltmeter, and milliammeter. We need to evaluate the resistance of each.

2. **Ammeter**:
- An ammeter is designed to measure current. It is typically constructed by converting a galvanometer into an ammeter by adding a low resistance known as a shunt resistor in parallel.
- Although an ammeter has low resistance, it is still higher than that of a galvanometer because of the shunt resistance added.

3. **Voltmeter**:
- A voltmeter measures voltage and is constructed by converting a galvanometer into a voltmeter by adding a high resistance in series.
- This high resistance is necessary to ensure that the voltmeter does not draw significant current from the circuit, which would affect the measurement. Therefore, a voltmeter has very high resistance.

4. **Milliammeter**:
- A milliammeter is a type of ammeter that measures smaller currents (in milliamperes). It is also made by converting a galvanometer into a milliammeter, similar to an ammeter, but it is designed for lower current ranges.
- Like the ammeter, it has a low resistance, but it is still more than that of a galvanometer.

5. **Galvanometer**:
- A galvanometer is an instrument that can detect small currents and is very sensitive. It has the smallest resistance among all these meters because it is designed to operate with minimal current and does not require additional resistances to function properly.

6. **Conclusion**:
- Among the options, the galvanometer has the smallest resistance compared to the ammeter, voltmeter, and milliammeter.

### Final Answer:
The electrical meter with the smallest resistance is the **Galvanometer**.