What is the space between two consecutive grooves on the CD

  • Context: Undergrad 
  • Thread starter Thread starter thuanthuan
  • Start date Start date
  • Tags Tags
    Space
Click For Summary
SUMMARY

The discussion focuses on measuring the spacing between grooves on a compact disc using diffraction principles. By positioning the disc at a specific distance from the eye and observing the light spectrum, users can calculate the angle for the first-order maximum of violet light. Utilizing Equation 38.10 from "Fundamentals of Physics, 7th edition," participants can determine the groove spacing, which is standardized at 1.6 micrometers. The experiment combines practical observation with theoretical calculations to validate the groove spacing measurement.

PREREQUISITES
  • Understanding of diffraction and interference patterns
  • Familiarity with basic optics concepts
  • Knowledge of the wavelength of light, particularly violet light
  • Ability to perform trigonometric calculations
NEXT STEPS
  • Study the principles of diffraction grating and its applications
  • Learn how to apply the diffraction equation d sin(a) = m λ in practical scenarios
  • Explore the properties of light wavelengths, focusing on the visible spectrum
  • Conduct experiments measuring light diffraction using various materials
USEFUL FOR

Physics students, educators, optical engineers, and anyone interested in the practical applications of diffraction and light behavior in experimental settings.

thuanthuan
Messages
4
Reaction score
0
Stand a couple of meters from a lightbulb.
Facing away from the light,
hold a compact disc about 10 cm
from your eye and tilt it until the reflection
of the bulb is located in the
hole at the disc’s center. You should
see spectra radiating out from the
center, with violet on the inside and
red on the outside. Now move the
disc away from your eye until the violet
band is at the outer edge. Carefully
measure the distance from your
eye to the center of the disc and also
determine the radius of the disc. Use
this information to find the angle a to
the first-order maximum for violet
light. Now use Equation 38.10 to determine
the spacing between the
grooves on the disc. The industry
standard is 1.6
m. How close did
you come?

( Fundamentals of Physics, p1226, 7th edition)

Can you tell me how to perform this experiment ? .. and also prove that it's true.
I don't understand it.
Thank you.
 
Last edited:
Science news on Phys.org
note that equation 3.10: for diffraction grating, the condition for maxima in the interference pattern at the angle a is d.sina=m.lambda
(d = slit spacing. m=0,1,2... - order number, lambda=wavelength)
 

Similar threads

Diffraction Gratings: Calculating Wavelength for CD ROM
  • · Replies 6 ·
Replies
6
Views
2K
Undergrad Moving through space vs sitting in an expanding space
  • · Replies 6 ·
Replies
6
Views
2K
High School Gravity Between Two Stars 45 Billion Light Years Away?
  • · Replies 5 ·
Replies
5
Views
2K
High School Can we say a photon doesn't exist until the wavefunction collapses?
  • · Replies 16 ·
Replies
16
Views
3K
Undergrad Diffraction Gratings: Understanding Spectroscopes Using Pringles Tubes
  • · Replies 4 ·
Replies
4
Views
2K
Undergrad Escape from Two Black Holes? Solve the Mystery!
  • · Replies 2 ·
Replies
2
Views
2K
Undergrad Mach-Zehnder interferometer, but with an entangled beam?
  • · Replies 33 ·
2
Replies
33
Views
3K
Undergrad How to Measure Speed of Light & Is It Constant?
  • · Replies 13 ·
Replies
13
Views
3K
High School Questions regarding expansion, the vacuum in space, and black holes
  • · Replies 6 ·
Replies
6
Views
2K
Undergrad Perceived Speed of Objects in Space
  • · Replies 5 ·
Replies
5
Views
2K