When light is refracted into a denser medium,(A) its wavelength and frequency both increase(B) its wavelength increases but the frequency remain unchanged(C) its wavelength decreases but the frequency remain unchanged(D) its wavelength and frequency both decrease

When light is refracted into a denser medium, neither its wavelength nor its frequency changes. The correct answer is (C) its wavelength decreases, but the frequency remains unchanged.

Refraction is the bending of light as it passes from one medium to another, such as from air to water or from air to glass. When light waves encounter a boundary between two media with different optical densities, they change direction due to the change in the speed of light. This change in direction is accompanied by a change in the wavelength and velocity of the light, while the frequency remains constant.

According to Snell's law, the ratio of the sine of the angle of incidence to the sine of the angle of refraction is equal to the ratio of the velocities of light in the two media. Since the velocity of light is lower in a denser medium, the light waves will experience a decrease in wavelength while maintaining the same frequency.

In summary, when light is refracted into a denser medium, the wavelength decreases, but the frequency remains unchanged.