What Is the Wavelength of a Laser Used in CD Data Retrieval?

  • Thread starter Thread starter jsmith613
  • Start date Start date
  • Tags Tags
    Laser Wavelength
AI Thread Summary
A CD retrieves data by using a laser to read the encoded bumps on its surface, which represent digital information. The height of these bumps is 160 nm, and the laser's wavelength must be appropriate to accurately detect these features. To calculate the wavelength, one must consider the relationship between the laser's wavelength and the dimensions of the bumps. A diagram illustrating the interaction between the laser and the CD surface would enhance understanding. Clarification on these concepts is needed for a complete solution.
jsmith613
Messages
609
Reaction score
0

Homework Statement



A CD stores data in digital form by encoding it into a grooves as a series of bumps of height 160 nm above the base of the groove. Explain how infromation is picked up from the CD using a laser and calculate its wavelength.

Can someone please explain how to do this question

Homework Equations



NONE

The Attempt at a Solution



I don't understand the question at all! Sorry!
 
Physics news on Phys.org
If possible could someone also add a diagram to help me
 

Thread 'Errors and significant figures'

I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
View full post »
Thread 'A cylinder connected to a hanging mass'

Thread 'A cylinder connected to a hanging mass'

Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
View full post »

Similar threads

Describing lasers, their use, and link to science
Replies
6
Views
2K
Estimation of data stored on a CD
Replies
9
Views
2K
How Does a Laser's Resonant Cavity Create Multiple Wavelengths?
Replies
7
Views
2K
Using Blue Laser Light for CD Players: Manufacturing Implications
Replies
1
Views
2K
How does Band Gap and Refractive index relate to Wavelength?
Replies
2
Views
2K
Laser safety / measuring errors question
Replies
7
Views
2K
Predicting Changes in Interference Patterns using Laser Interference Equations
Replies
3
Views
2K
What is the wavelength of the helium-neon laser beam in the liquid?
Replies
1
Views
14K
What is the effect of light on the weight of a glass prism?
Replies
4
Views
2K
Thin-Film Interference (2 Wavelengths)
Replies
14
Views
3K

Hot Threads

Recent Insights

Back
Top