The range of ammeter can be………………………but can not be……………….. .

Answer

### Step-by-Step Solution:

1. **Understanding the Ammeter**: An ammeter is a device used to measure the current flowing through a circuit. It is designed to have a specific range, which indicates the maximum current it can measure accurately.

2. **Increasing the Range of an Ammeter**: The range of an ammeter can be increased by connecting a low resistance in parallel with it. This is known as a shunt resistor. When a shunt resistor is added, it allows a portion of the current to bypass the ammeter, effectively increasing the total current that can be measured.

3. **Effect of Parallel Resistance**: When a low resistance is connected in parallel, the equivalent resistance of the circuit decreases. According to Ohm's law, if the total resistance decreases, the current flowing through the circuit increases. This means that the ammeter can now measure a higher current than it could before.

4. **Limitation of Ammeter Range**: While the range of an ammeter can be increased, it cannot be decreased. This is because the ammeter is designed to measure current within a specific range, and reducing its range would not be feasible without altering the internal components of the ammeter itself.

5. **Conclusion**: Therefore, we can fill in the blanks as follows: "The range of an ammeter can be increased but cannot be decreased."

### Final Answer:
The range of an ammeter can be **increased** but cannot be **decreased**.

---