How do ultrasonic leak detectors identify refrigerant leaks?

Ultrasonic leak detectors identify refrigerant leaks by detecting the high-frequency sound waves produced by the escaping gas. When refrigerant escapes through a leak, it creates turbulence and sound waves that travel through the air. The ultrasonic leak detector is equipped with sensitive microphones that can pick up these high-frequency sounds, which are typically above the range of human hearing. This method is effective because even small leaks can generate detectable ultrasonic sound, allowing technicians to identify leaks accurately without needing direct contact with the refrigerant. The other options do not pertain to the unique functioning of ultrasonic detectors, which specifically rely on sound frequency rather than temperature, pressure changes, or refrigerant level analysis.