AP Physics 2 : Wave Interference and Diffraction

Example Questions

Example Question #1 : Waves

Wave interference is __________ when the amplitudes of the waves add together to make a larger wave overall, while it is __________ when the amplitudes of the waves work against one another to make a smaller wave overall.

destructive . . . constructive

refractive . . . detractive

refractive . . . constructive

diffusive . . . destructive

constructive . . . destructive

constructive . . . destructive

Explanation:

When waves add together and make a larger wave, think of them as constructing a big wave. On the other hand, waves that make a smaller wave are said to be destructive because they are "destructing" each other and making a smaller wave, or no wave at all.

Example Question #2 : Waves

When light __________ interferes, the result is __________ light overall, and when light __________ interferes, the result is __________ light overall.

additionally . . . brighter . . . subtractively . . . less bright

destructively . . . brighter . . . contsructively . . . less bright

None of these

constructively . . . brighter . . . destructively . . . less bright

subtractively . . . brighter . . . additionally . . . less bright

constructively . . . brighter . . . destructively . . . less bright

Explanation:

Because light has properties of waves, it can have interference. When two crests of the wave meet, this is known as constructive interference, and results in the two crests adding, meaning the light gets brighter. When a crest and a trough meet, this is known as destructive interference, and results in the two partially or completely cancelling each other out, making the observed light less bright.

Example Question #3 : Wave Interference And Diffraction

Suppose that monochromatic light is passed through a sheet of glass from air. As it travels through the glass, it is refracted. Which of the following parameters of the light does not remain the same?

Wavelength

Frequency

Period

Energy

All of these parameters stay the same