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This causes the pencil to appear higher and the water to appear shallower than it really is. The lines of sight (shown as dashed lines) intersect at a higher position than where the actual rays originated.
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Once the rays reach the eye, the eye traces them back as straight lines (lines of sight). This is due to the bending of light rays as they move from the water to the air. Looking at a straight object, such as a pencil in the figure here, which is placed at a slant, partially in the water, the object appears to bend at the water's surface. Refraction occurs when light goes through a water surface since water has a refractive index of 1.33 and air has a refractive index of about 1. Refraction in a water surfaceĪ pencil part immersed in water looks bent due to refraction: the light waves from X change direction and so seem to originate at Y. How much a wave is refracted is determined by the change in wave speed and the initial direction of wave propagation relative to the direction of change in speed.įor light, refraction follows Snell's law, which states that, for a given pair of media, the ratio of the sines of the angle of incidence θ 1. Refraction of light is the most commonly observed phenomenon, but other waves such as sound waves and water waves also experience refraction. The redirection can be caused by the wave's change in speed or by a change in the medium. In physics, refraction is the redirection of a wave as it passes from one medium to another. A ray of light being refracted in a plastic block.
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