Certified Professional Photographer (CPP) Practice Exam

What happens to white light when it passes through a prism?

1. It intensifies

2. It separates into a rainbow of color

3. It becomes ultraviolet

4. It reverses direction

The correct answer is: It separates into a rainbow of color

When white light passes through a prism, it separates into a spectrum of colors, creating a rainbow effect. This phenomenon is known as dispersion. The reason this occurs is that light, which is made up of multiple wavelengths, travels at different speeds when it enters a denser medium like glass. Each wavelength is refracted, or bent, by a different amount due to distinct refractive indices for each color. As a result, colors like red, orange, yellow, green, blue, indigo, and violet emerge in a continuous spectrum. This principle is fundamental in understanding how light interacts with materials, which is integral in fields such as photography, optics, and physics. The other options do not accurately describe the effect of a prism on white light. White light does not intensify or change to ultraviolet; it also does not reverse direction. Instead, it is the bending and splitting of the light that leads to the colorful display, which truly highlights the concept of dispersion.