Name the device that can be used to measure the number of wavelengths of light in a given distance.

Explanation

To answer the question, "Name the device that can be used to measure the number of wavelengths of light in a given distance," we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for a specific device that can measure the number of wavelengths of light over a certain distance. This implies that the device must be capable of analyzing light waves and their properties.

2. **Identifying the Device**: The device that fits this description is the **optical interferometer**. This instrument is specifically designed to work with light waves and can measure various properties related to them.

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