# Diffraction, interference, single and double slit setups

• Yangi
In summary, the conversation discusses correcting a calculation error, using the argument ##\theta## in the ##\sin## function, and approximating ##\sin{\theta}## with ##\theta## for small values. The final calculation results in a value of 0.36 degrees.
Yangi
Homework Statement
Hey,
due to the corona—virus here in Germany all schools are closed down. Today our teacher gave us two tasks but I'm not sure which formulars I should use.

1.Calculate the Angel below the 3rd.diffraction minimum behind a single slith that's 0.3 mm width. The laserpointer is a red one with a wave length of 630nm.

2.A parallel red light falls through a double slit. Interference appears on a screen that's 3meters away from the lightsource.The distance between the 1st and zero maximum is 4mm. The column spacing d=0,5mm.
Calculate the Wave length of the red light

Relevant Equations
I have added a picture with my attempts to find a solution and equations..
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#### Attachments

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I think you might have forgotten to multiply by 3 on your calculator for the first part. Also make sure to write ##\theta## in the argument of the ##\sin## function in your working! Also note that for small ##\theta##, we have ##\sin{\theta} \approx \theta## so often we can just use ##\theta = \frac{\lambda}{s}## - though in this case it's small enough that the two are the same to pretty high precision!

I agree with your part 2.

Last edited by a moderator:
berkeman
Thank your for the fast reply. I corrected the first one now I got 0.30 degree is this right ?

Yangi said:
Thank your for the fast reply. I corrected the first one now I got 0.30 degree is this right ?

If you do want to convert it to degrees, I get a value of 0.36 degrees.

## 1. What is diffraction?

Diffraction is the bending or spreading of waves as they pass through an opening or around an obstacle. It occurs with all types of waves, including light, sound, and water waves.

## 2. How does interference occur?

Interference is the result of two or more waves overlapping and creating a new wave pattern. This can happen when waves from different sources meet or when waves reflect off of a surface and overlap with the original wave.

## 3. What is a single slit setup?

A single slit setup is an experiment that involves passing a beam of light through a narrow slit and observing the resulting diffraction pattern. This can help determine the wavelength of the light and the width of the slit.

## 4. How does a double slit setup work?

In a double slit setup, a beam of light is passed through two narrow slits, creating an interference pattern on a screen behind the slits. This pattern is caused by the overlapping of the waves from each slit, resulting in areas of constructive and destructive interference.

## 5. What are some real-life applications of diffraction and interference?

Diffraction and interference are important phenomena in many fields, including optics, acoustics, and radio waves. They are used in technologies such as holography, fiber optics, and radio telescopes. They also play a role in everyday objects, such as CDs and DVDs, which use interference patterns to store and read data.

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