Competency #9
Answer and Explanation
When white light goes from the air through a glass prism, the light gets separated into all the colors of the rainbow. This occurs because:
Answer:
The correct answer is B.
Consider the definitions of the terms:
| Term | Definition |
|---|---|
| 1. Reflection | the change in the direction of a light wave when it bounces off of a surface. |
| 2. Refraction | the change in the direction of a light wave when it travels from one substance into another substance. |
| 3. Diffraction | the bending of light around the edge of an object. |
| 4. Polarization | the process of selecting light waves that are all vibrating in the same plane and removing those that are not. |
- The prism reflects each color of light slightly differently. Some light is reflected off the surface of the prism. However, it is the light traveling through the prism that creates the ‘rainbow' so this can't be the answer.
- The prism refracts each color of light at a slightly different angle. This is true. The index of refraction (the angle at which light is bent when transition from one transparent medium to another) is different for each wavelength of light. Since each wavelength is bent differently, the light that leaves the prism it is no longer coalesced as white light, it has been separated and you can see each color.
- The prism polarizes the light. The only visible change in polarized light versus unpolarized light is the intensity of the light. Polarized white light still appears white, it is just dimmer. This is not the answer.
- The prism diffracts each color of light differently. The ‘rainbow' is created by light traveling through the prism, not by light bending around the edges of the prism. This is not the answer.
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