A Level Physics Practice Exam

How is a progressive wave characterized?

1. A wave that is stationary

2. A wave that changes medium

3. A wave that moves through the medium

4. A wave with fixed endpoints

The correct answer is: A wave that moves through the medium

A progressive wave is characterized by its ability to move through a medium while transferring energy from one point to another. This motion distinguishes progressive waves from other types of waves, such as stationary waves, which do not propagate and instead remain fixed in certain positions. In a progressive wave, the particles of the medium oscillate around their equilibrium positions as the wave passes through, allowing energy to be transmitted without the bulk movement of matter. This is essential in understanding how waves like sound or electromagnetic waves behave in various environments, as they continuously propagate outward from their source. Other options reflect different characteristics of waves that do not accurately describe the nature of a progressive wave. For instance, stationary waves, which result from the interference of two waves moving in opposite directions, remain in fixed positions and don't have a net movement across the medium. Moreover, while waves can change mediums, a progressive wave is not defined by changing its medium but rather by its ability to propagate through a medium. Lastly, having fixed endpoints relates more to the behavior of standing waves than to the propagation of a wave. Thus, the correct characterization of a progressive wave is its movement through a medium.