Michigan Test for Teacher Certification (MTTC) Secondary Integrated Science Practice test

What describes longitudinal waves?

1. They are perpendicular to the wave of motion

2. They are parallel to the wave of motion

3. They have higher frequencies than transverse waves

4. They do not transfer energy

The correct answer is: They are parallel to the wave of motion

Longitudinal waves are characterized by particle motion that occurs parallel to the direction of wave travel. In a longitudinal wave, the oscillations of particles of the medium are aligned in the same direction as the wave is moving, which creates alternating regions of compression and rarefaction. Examples of longitudinal waves include sound waves in air, where areas of high pressure (compressions) and low pressure (rarefactions) propagate through the medium. The parallel nature of the particle motion to the direction of wave propagation is fundamental to understanding how these waves transport energy and information from one location to another. This is in contrast to transverse waves, where the particle motion is perpendicular to the direction of wave propagation. The other options do not accurately describe the essential characteristics of longitudinal waves. For instance, characteristics such as frequency can vary independently of the type of wave, and all waves intrinsically transfer energy across distances.