Question

When a ray of light passes from a denser to a rarer medium, its wavelength ______.

Options

• decreases

• increases

Answer 1

When a ray of light passes from a denser to a rarer medium, its wavelength increases.

Explanation:

The velocity of light varies across different media due to their different optical densities. In denser media, light propagates at a reduced velocity, but in rarer media, it propagates at an increased velocity. According to the equation c = λ × f, where c represents the speed of light, λ denotes the wavelength, and f signifies the frequency, if the speed of light decreases (as occurs when entering a denser medium) while f remains constant, then λ must increase to compensate. Conversely, when light transitions from a denser to a rarer medium, its velocity increases, resulting in a longer wavelength.