ARDMS Ultrasound Physics & Instrumentation Practice Exam

Which of the following statements about wavelength is NOT true?

1. Wavelength is determined by both the source and medium

2. Wavelength increases with decreasing frequency

3. Wavelength is equal to the period divided by the frequency

4. Wavelength decreases with increasing frequency

The correct answer is: Wavelength is equal to the period divided by the frequency

Wavelength is a critical property in ultrasound physics, defined as the distance between successive peaks (or troughs) in a wave, and it is influenced by the frequency of the wave and the speed of sound in the medium. To understand the correct statements related to wavelength, it's essential to first clarify the relationships involved. Wavelength is indeed determined by both the source (which produces the sound or ultrasound wave) and the medium (through which the wave travels). In different media, the speed of sound varies, which affects the wavelength in conjunction with the frequency. The relationship between frequency, wavelength, and the speed of sound in a medium is given by the formula: wavelength = speed of sound / frequency. This clearly shows that as frequency increases, wavelength decreases, affirming that wavelength is inversely related to frequency. This means that if you have a higher frequency, there will be shorter wavelength, and conversely, lower frequency will result in longer wavelength. Thus, when considering the provided answer choice, it highlights a misunderstanding of the correct mathematical relationship. The correct statement about wavelength is that it is correctly defined by the formula which connects wavelength, frequency, and speed. Therefore, saying that wavelength is equal to the period divided by frequency does not hold,