Single Slit Interference Pattern: Increased Distance

In summary, when the screen is moved further away, the effect on the pattern would be wider bright fringes, decreased light intensity of the bright fringes, and the bright fringes appearing closer together. This is due to the spreading of light as the distance between the slit and screen increases. It is unclear whether the dark fringes would actually get smaller or if it is just a perception. To answer this, one must consider relevant expressions and quantities related to the appearance of bright and dark fringes.
  • #1
belbin09
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Homework Statement
A laser emitting light with a wavelength of 560 nm is directed at a single slit, producing an interference pattern on a screen that is 3.0 m away. The central maximum is 5.0 cm wide.

What would the effect on this pattern be, if the screen was moved further away?
Relevant Equations
Δy = λL/w
ATTEMPT AT SOLUTION

The effect on the pattern when the screen is moved further away is the bright fringes would become wider, the light intensity of the bright fringes would decrease, and the bright fringes will appear closer together.

REASONING

I answered this question based on how light works against a screen in general. The part I get stuck on is how the dark fringes would appear. I state that the bright fringes "appear" closer together because as the distance between the slit and the screen increases the bright fringes would become wider, spreading the light outwards making the dark fringes harder to distinguish. Would the dark fringes actually get smaller or is it just a perception?
 

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  • #2
What expressions do you know about where the bright and dark fringes appear? What quantities are relevant? Start from there.
 

FAQ: Single Slit Interference Pattern: Increased Distance

What is a single slit interference pattern?

A single slit interference pattern is a pattern of light and dark bands that is created when a beam of light passes through a narrow slit. This phenomenon is caused by the interference of the light waves as they diffract and overlap with each other.

How does increasing the distance affect the single slit interference pattern?

Increasing the distance between the slit and the screen where the pattern is observed will cause the bands of the interference pattern to become wider and more spread out. This is because the light waves have more time and space to diffract and interfere with each other before reaching the screen.

Why does the single slit interference pattern become less distinct with increased distance?

The single slit interference pattern becomes less distinct with increased distance because the light waves have more time and space to diffract and interfere with each other, causing the bands to overlap and become less defined. This is known as the diffraction limit.

How does the width of the slit affect the interference pattern at increased distances?

The width of the slit affects the interference pattern at increased distances by determining the spacing between the bands. A narrower slit will result in wider bands, while a wider slit will result in narrower bands. This is because the width of the slit affects the diffraction of the light waves.

Can the single slit interference pattern be observed at any distance?

Yes, the single slit interference pattern can be observed at any distance. However, the pattern will become less distinct and eventually disappear as the distance increases due to the diffraction limit. Additionally, at very large distances, other factors such as atmospheric conditions may also affect the visibility of the interference pattern.

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