Question

When light travels from one medium to other which property remains constant ?

• A. Frequency
• B. Wavelength
• C. Velocity
• D. None of these

Answer 1

Answer:

A. Frequency

• Frequency (ν): This is the fundamental characteristic of light, which depends solely on the source of the light. When light crosses the interface between two different optical media, the frequency remains unchanged.

• Wavelength (λ): When light enters a denser medium from a rarer medium, its speed decreases, which leads to a decrease in its wavelength. Conversely, when it moves into a rarer medium, the wavelength increases.

• Velocity (v): The speed of light is directly proportional to its wavelength (v = νλ). Since the frequency is constant and the wavelength changes based on the refractive index of the medium, the speed of light changes accordingly.

• Refractive Index (n): The change in speed is defined by the refractive index of the medium, calculated as n = c/v, where c is the speed of light in a vacuum.

• Physical significance: Because the color of light is determined by its frequency, the color of light remains constant even after refraction.