How is reflection used in CDS?
It uses optical systems with a high precision laser to read the data. It relies on the aluminum layer of the CD to reflect the laser beam, and uses the reflected beam to determine the position of the features.
Are CDS reflective?
The surface of a CD is reflective because the disc is coated with a thin layer of aluminum or sometimes gold. The shiny metal layer reflects the laser that is used to read or write to the device.
What is CD on a flashlight?
By understanding candelas (cd), we can get a good idea of whether or not our flashlight will have a “floody” or “focused” beam. According to Wikipedia, it is called such because 1 candela is approximately equivalent to the output from a candle, candelas measure the intensity of light in a single direction.
What do you see on holding a CD in the sun?
When you hold a CD under the sunlight it reflects a rainbow due to it’s reflecting nature. The reflecting colors that can be seen from a CD are interference colors, for example the shifting colors that we see on a soap bubble. It can be thought of as light being made up of waves, like the waves in the ocean.
Why rainbow is formed on CD?
Why does a CD reflect rainbow colors? Like water drops in falling rain, the CD separates white light into all the colors that make it up. You can think of light as as being made up of waves-like the waves in the ocean. When light waves reflect off the ridges on your CD, they overlap and interfere with each other.
Why do rainbows appear after rain?
When can you see a rainbow? A rainbow requires water droplets to be floating in the air. That’s why we see them right after it rains. The Sun must be behind you and the clouds cleared away from the Sun for the rainbow to appear.
Why are CDs iridescent?
The colors that you see on the CD are created by white light reflecting from ridges in the metal. When light reflects off or passes through something with many small ridges or scratches, you often get rainbow colors and interesting patterns. These are called interference patterns.
Why we can see rainbows on the CD by varying with angle?
The colours which overlap (peaks of waves overlap) are seen brighter than the colours which cancel each other (peak of one wave overlaps with the trough of the other). The distance between eye of the observer and each pit varies. The angle at which the observer sees the CD controls the colors seen.