Sonar is a device for

Options

A. Location and ranging of aircrafts·
B. Location and ranging of submarines
C. Producing a musical Iiote of high quality
D. Measuring frequency of musical notes

Explanation

### Step-by-Step Solution:

1. **Understanding Sonar**: Sonar stands for Sound Navigation and Ranging. It is a technology that uses sound waves to detect and locate objects underwater.

2. **Function of Sonar**: The primary function of sonar is to send sound waves into the water. These sound waves travel until they hit an object (like the seabed or a submarine) and then reflect back to the source.

3. **How Sonar Works**: When a ship or submarine sends out a sound wave, it measures the time taken for the echo to return. By knowing the speed of sound in water, the device can calculate the distance to the object based on the time taken for the sound to travel to the object and back.

4. **Applications of Sonar**: Sonar is primarily used in submarines and ships for navigation, locating underwater objects, and mapping the sea floor. It is not used for producing musical notes or measuring the frequency of musical notes.

5. **Eliminating Incorrect Options**:
- **Musical Notes**: Sonar is not related to music, so this option can be eliminated.
- **Aircrafts**: Sonar is not typically used in aircraft; instead, radar is used for navigation and detection in the air. Therefore, this option can also be eliminated.

6. **Correct Answer**: The correct answer is that sonar is a location and ranging device used in submarines.