A flash of red light and a flash of blue light enter a glass cube perpendicular to its surface at the same time. after passing through the block, the red light pulse exits first.
For any medium, other than vacuum, the index of refraction for red light is slightly lower (closer to 1 ) than that for blue light. This means that when light goes from vacuum (or air) into glass, the red light deviates from its original direction less than does the blue light. Also, as the light reemerges from the glass into vacuum (or air), the red light again deviates less than the blue light. If the two surfaces of the glass are parallel to each other, the red and blue rays will emerge traveling parallel to each other, but displaced laterally from one another.
what is refractive index?
The ratio between the speed of light in medium to speed in a vacuum is the refractive index. When light travels in a medium other than the vacuum, the atoms of that medium continually absorb and re-emit the particles of light, slowing down the speed light.
learn more about refractive index from here: brainly.com/question/28203787
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