Understanding the Anemometer and Wind Speed Measurement

The question asks about the instrument used for measuring a specific physical quantity. The instrument mentioned is the 'Anemometer'. We need to identify what the Anemometer measures from the given options.

Let's look at the options provided:

• wind speed
• light speed
• sound speed
• temperature

What Does an Anemometer Measure?

An Anemometer is a common weather instrument used to measure the speed of the wind. It is a standard component of a weather station. Different types of anemometers exist, such as cup anemometers, propeller anemometers, and ultrasonic anemometers, but they all serve the primary purpose of measuring wind speed.

Let's consider the other options to confirm why they are incorrect:

• Light speed: The speed of light is a fundamental constant and is not measured with an anemometer. Instruments related to measuring light might include photometers or devices for measuring properties like intensity or wavelength.
• Sound speed: The speed of sound in a medium depends on its properties like temperature and composition. It is typically measured using techniques involving timing sound pulses, not an anemometer.
• Temperature: Temperature is measured using a thermometer, not an anemometer.

Based on the definition and function of an Anemometer, it is used specifically for measuring wind speed.

Therefore, the instrument 'Anemometer' is used for measuring the wind speed.