Calculating the Fringe Width without the value of its Wavelength

In summary, Young's fringes were observed on a screen with a distance of 58mm across 20 fringe spacings when the screen was 0.60m away from the slits. When the screen was moved to a distance of 0.80m, the distance across 20 fringe spacings became 74mm. Using the equation Y = D(lamda)/d, where Y is the fringe width, D is the distance from slits to screen, and d is the spacing between slits, the wavelength can be calculated by finding the value of D1 and substituting it into the equation.
  • #1
AJ786
3
0

Homework Statement



Young's fringes, produced by monochromatic laser light passing through slits 0.60mm apart, are viewed on a screen. The distance accrose 20 fringe spacings on the screen is 58mm. When the screen is moved 0.80m away from the slits, the distance across 20 fringe spacings becomes 74mm.

Homework Equations



Y = D(lamda) / d

Y = Fringe Width
D = Distance from slits to screen
d = spacing between slits
(lamda) = Wavelength

The Attempt at a Solution

 
Last edited:
Physics news on Phys.org
  • #2
In the experiment wavelength and slit width is constant. There fore
Y1/Y2 = D1/D2.
Y1 and Y2 is given. D1 is not given. But D2 = D1 + 0.80 m.
Substitute these values in the above relation and find D1.
Then using the relevant equation, you can find the wavelength.
 
  • #3
Are Y1 and Y2 0.60mm and 74mm as Y is what I need to calculate so surely this would not be given to me within the question ?
 
Last edited:

What is the fringe width?

The fringe width is the distance between two consecutive bright or dark fringes in a fringe pattern, such as in a double-slit experiment. It is a measure of the interference pattern produced by waves, and is affected by the wavelength of the waves and the distance between the sources of the waves.

How is the fringe width calculated?

The fringe width can be calculated using the following formula:
Fringe width = (Distance between slits/distance to screen) x (Wavelength of waves)

Can the fringe width be calculated without knowing the wavelength?

Yes, the fringe width can be calculated without knowing the wavelength if the distance between the slits and the distance to the screen are known. The formula for this scenario is:
Fringe width = (Distance between slits/distance to screen) x (Distance between fringes)

What is the importance of knowing the fringe width?

Knowing the fringe width is important in understanding the behavior of waves and the phenomenon of interference. It also allows for the calculation of other important quantities, such as the distance between slits or the wavelength of the waves.

Can the fringe width change in different situations?

Yes, the fringe width can change depending on the conditions of the experiment. It can be affected by factors such as the wavelength of the waves, the distance between the sources of the waves, and the distance to the screen. Additionally, different setups, such as using a different number of slits, can also affect the fringe width.

Similar threads

  • Introductory Physics Homework Help
Replies
3
Views
547
  • Introductory Physics Homework Help
Replies
5
Views
1K
  • Introductory Physics Homework Help
Replies
4
Views
812
  • Introductory Physics Homework Help
Replies
1
Views
826
  • Introductory Physics Homework Help
Replies
1
Views
2K
  • Introductory Physics Homework Help
Replies
5
Views
2K
  • Introductory Physics Homework Help
Replies
7
Views
5K
  • Introductory Physics Homework Help
Replies
6
Views
863
  • Introductory Physics Homework Help
Replies
3
Views
2K
  • Introductory Physics Homework Help
Replies
6
Views
1K
Back
Top