Which of the following statements is not true about refraction?
Refraction occurs when light's velocity changes.
The angle between the refracted ray and the normal is called the angle of refraction.
When light moves from a rarer to a denser medium, it bends toward the normal.
The path of a light ray that crosses the boundary between two different media is irreversible.
the last one
To determine which statement is not true about refraction, we'll need to evaluate each statement individually.
1. Refraction occurs when light's velocity changes.
This statement is true. Refraction is the bending of light as it passes from one medium to another with a different refractive index. When light enters a medium where its velocity changes, it causes the light ray to change direction.
2. The angle between the refracted ray and the normal is called the angle of refraction.
This statement is also true. The angle between the refracted ray and the normal is indeed called the angle of refraction. The normal is an imaginary line perpendicular to the surface of the medium where the refraction is occurring.
3. When light moves from a rarer to a denser medium, it bends toward the normal.
This statement is true. When light travels from a medium with a lower refractive index (rarer medium) to a medium with a higher refractive index (denser medium), it bends toward the normal. This bending is due to the change in the speed of light as it enters a medium with a different refractive index.
4. The path of a light ray that crosses the boundary between two different media is irreversible.
This statement is not true. The path of a light ray that crosses the boundary between two different media is reversible. When light passes from one medium to another, it changes direction at the boundary. However, if the light ray encounters a second boundary between two media, it can again change direction at that boundary, effectively reversing its path.
Based on this evaluation, the statement that is not true about refraction is: "The path of a light ray that crosses the boundary between two different media is irreversible."