The correct answer is option 3: change in speed of light.

Refraction refers to the bending of light as it passes from one transparent medium to another. It occurs because light travels at different speeds in different mediums. When light enters a different medium, such as from air to water or from air to glass, its speed changes. This change in speed causes the light waves to bend or change direction.

Option 1, change in temperature of the media, is not the correct explanation for refraction. While temperature can affect the density of a medium, which in turn can affect the speed of light, refraction is primarily caused by the change in speed of light rather than temperature.

Option 2, change in the amplitude of light, does not directly cause refraction. Amplitude refers to the height or intensity of the light waves, and while it can affect the overall brightness or intensity of light, it does not cause the bending or change in direction of light during refraction.

Option 4, internal property of light, is vague and does not provide a specific explanation for refraction. Refraction is an external phenomenon that occurs when light interacts with different mediums.

The correct explanation is that refraction of light is due to the change in speed of light as it