Answer:
Step-by-step explanation:
When dealing with optics, there is an incident wave, a reflected wave, and a transmitted wave. An incident wave is the initial wave coming out from the source, like a flashlight.
Then the reflected wave is created when the incident wave encounters an interface like a piece of glass. The reflected wave will reflect like you would expect.
Then, the transmitted wave is the wave which passes through the interface and continues.
So, a good question would be to ask for the value of the reflected wave function given an initial incident wave.
Another example entirely would be to look at the reflected wave on a tensioned string. If you shake a string up and down, a wave will be sent through it. Once hitting the wall, the wave will reflect back. A good question there is asking how the amplitude of the wave changed.