A diffraction grating formed by parallel adjacent tracks on a CDROM

In summary, a diffraction grating on a CDROM works by using a series of parallel tracks to diffract light and create a distinct pattern of light and dark bands. Its main purpose is to encode data on the disc, and it is created through a process called photolithography. The spacing of the tracks directly affects the diffraction pattern, and it has various uses besides data storage, including scientific and engineering applications and consumer products.
  • #1
help I have 12 hours
12
2
Homework Statement
The parallel tracks on a CD-ROM reflect light just like a diffraction grating. Looking at a CD-ROM under white light, you observe a bright reflection of 475 nm blue light at 40.6° from normal incidence. The next bright blue reflection occurs at 77.2°.

Calculate the spacing between the CD-ROM tracks. Show your work here, and then enter your final numeric answer in the next answer box.
Relevant Equations
(d) sin(theta)=(wave length)*m
(d)sin(40.6)=(475*10^-9)(1)

d=730*10^-9 (m)

prof says answer is 1460*10^-9 (m) tho
 
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  • #2
I agree with your answer but something is weird in general. The 77.2 degree don't fit to the next band. 1.6 micrometers is the usual separation for a CD. 740 nm for a DVD.
 

1. What is a diffraction grating on a CDROM?

A diffraction grating on a CDROM is a series of parallel, closely spaced tracks that are etched onto the surface of the disc. These tracks act as a diffraction grating, splitting light into its component wavelengths and producing a rainbow-like effect when viewed at certain angles.

2. How does a diffraction grating on a CDROM work?

The closely spaced tracks on a CDROM act as a diffraction grating, causing light to diffract and interfere with each other. This interference results in the splitting of light into its component wavelengths, producing a rainbow-like effect when viewed at certain angles.

3. What is the purpose of a diffraction grating on a CDROM?

The main purpose of a diffraction grating on a CDROM is to store and read data. The tracks on the disc are encoded with digital information, and the laser used to read the disc can detect the changes in the diffraction pattern to retrieve the data.

4. How is a diffraction grating on a CDROM made?

A diffraction grating on a CDROM is made by using a laser to etch tiny, closely spaced tracks onto the surface of the disc. These tracks are typically around 0.5 micrometers wide and are spaced about 1.6 micrometers apart.

5. What other applications does a diffraction grating on a CDROM have?

In addition to storing and reading data, a diffraction grating on a CDROM has other applications. It is commonly used in spectrometers to analyze the composition of substances, and in optical devices such as telescopes and cameras to improve image quality.

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