What determines the frequency of sound waves, and is it adjustable?

The frequency of sound waves is primarily determined by the sound source, which generates the waves based on its physical characteristics and the medium it travels through. In a sonography context, the transducer produces ultrasound waves by converting electrical energy into mechanical vibrations, which creates the sound waves at a specific frequency.

This frequency is set based on the design of the transducer and the characteristics of the piezoelectric crystals within it. Once a transducer is built to emit sound at a particular frequency, that frequency cannot be altered while the transducer is in use. Therefore, it is indeed accurate to say that the frequency is not adjustable once the transducer is in operation, which also aligns with the understanding that the sound source dictates this specific property.

Other options, such as environmental conditions, could influence the propagation of sound waves, but they do not change the frequency determined by the original sound source. Similarly, while transducer type might affect the range of frequencies that can be produced, it does not mean the frequency itself is adjustable once a specific transducer is employed. Wave speed is dependent on the medium through which the sound travels and is not a direct factor in determining or adjusting the frequency of the sound waves produced.