Which wave property can best explain the apparent bending of a pencil when its dipped in to a glass of water?
(1) Wave speed is less in water than in air.
(2) Ray direction is perpendicular to wavefronts
The wave property that best explains the apparent bending of a pencil when it is dipped into a glass of water is refraction. Refraction is a phenomenon that occurs when a wave, such as light or sound, passes from one medium to another with different properties, causing the wave to change its direction. In the case of the pencil in water, light waves are being refracted.
To understand how refraction causes the apparent bending of the pencil, you can follow these steps:
1. As light travels from one medium (such as air) to another (such as water), its speed changes. This change occurs because the refractive index, a property of the medium, determines how much the light is bent.
2. When the light from the pencil encounters the surface of the water, it slows down as it enters the water due to the higher refractive index of water compared to air.
3. According to the laws of refraction, when the light wave enters the water at an angle, it bends or changes direction. This change in direction at the interface between air and water causes the apparent bending of the pencil.
4. Once the light wave passes through the water, it returns to the air medium and speeds up again. As a result, the light bends again, but in the opposite direction, creating the illusion of the pencil appearing bent.
In summary, the refraction of light waves at the air-water interface is responsible for the apparent bending of the pencil when it is dipped into a glass of water.