MCAT® ExamChemical and Physical Foundations of Biological SystemsEasy
A student is analyzing the behavior of light as it passes from air into a block of glass. They observe that the light ray bends towards the normal. Which of the following statements best explains this phenomenon?
- AThe speed of light decreases as it enters the glass.
- BThe frequency of the light decreases as it enters the glass.
- CThe wavelength of the light increases as it enters the glass.
- DThe amplitude of the light wave increases as it enters the glass.
Show answer & explanationAnswer & explanation
Correct answer: A. The speed of light decreases as it enters the glass.
When light passes from a less dense medium (like air) to a more dense medium (like glass), its speed decreases. This change in speed causes the light ray to bend towards the normal, a phenomenon known as refraction, while its frequency remains constant.
Why the other options are wrong
- B. The frequency of light remains constant when it passes between different media.
- C. Since frequency is constant and speed decreases, the wavelength must also decrease (v = fλ).
- D. The amplitude change is related to reflection and transmission coefficients, not directly to the bending direction due to refraction.
Refraction of Light
Refraction is the bending of light as it passes from one medium to another due to a change in its speed.
- Light bends towards the normal when entering a denser medium.
- Light bends away from the normal when entering a less dense medium.
- The frequency of light remains constant during refraction.
Memory trick: Light Bends Speed Changes