Final answer:
When light travels from air into water, its speed decreases and so does its wavelength, while the frequency of the light remains unchanged.
Step-by-step explanation:
When a beam of light travels from air into water, its speed decreases. This is because water has a higher optical density than air, meaning that light waves travel more slowly in water than in air. As a result, when light goes from the air into a body of water, the correct answer to the multiple-choice question is (b) Decreases. Additionally, when this change occurs, the wavelength of the light also decreases because the speed of light is directly related to the wavelength and the frequency of the light remains unchanged.
Check Your Understanding
If we refer to a specific aspect of a beam of monochromatic light, such as the wavelength, when it passes from a vacuum (or air) into water, the wavelength decreases. Hence, the answer to Check Your Understanding 3 and 5 would be that the wavelength decreases and the speed decreases, aligning with multiple-choice answers (a).
TEST PREP
During preparation for tests on diffraction and interference, it's important to remember that the frequency of the light remains unchanged when light passes from one medium to another. This is because the frequency is a characteristic of the source and does not depend on the medium through which the light is traveling. Therefore, when a monochromatic beam of light passes from air into water, what remains unchanged is its frequency, making the correct answer to question 14 (c), the frequency of the light.