# Diffraction or Distraction?

• sailordragonball
In summary: Yes, there is an equation to calculate diffraction. However, I don't know what it is. Can you help me with that?What is the equation for diffraction?The equation for diffraction is:lambda = velocity / frequency
sailordragonball
Diffraction or Distraction??

A row of seats is parallel to a stage at a distance of 8.1 m from it. At the center and front of the stage is a diffraction horn loudspeaker. This speaker sends out its sound through an opening that is like a small doorway with a width D of 0.072 m. The speaker is playing a tone that has a frequency of 2.0 104 Hz. The speed of sound is 343 m/s. What is the separation between two seats, located near the center of the row, at which the tone cannot be heard?

Oops, I forgot to add that ... LOL ...

D = 0.072m (given)
f = 2.0 X 10^4 Hz or 20,000 Hz
v = 343 m/s (given)

... I know for the second part ... sin (theta) = (lambda / D)

... solving for lambda ... lambda = velocity / frequency ...

... lambda = 343 / 20000

... therefore: lambda = .01715m... this is where I'm stuck.

Am I missing an equation?

If the wavelength of a sound is bigger than the person/object/insect/whatever it is hitting, the sound won't be heard/clear. Also if there is not enough room for the wavelength to pass through, it will not work either (diffraction), apply this concept to your problem.

Last edited:
I don't understand ... I was reading from my Cutnell and Johnson 7th edition physics book - but, I couldn't understand the diffraction concept ... can you elaborate?

Last edited:
I went to the Hyperphysics website ... and got the jist of it ... but, it's not clear to me yet ... any other suggestions or walkthroughs?

Read those pages over and over until you get it, alternatively you can search on google for "diffraction". I think that between your textbook and the two websites you should have enough information to grasp the concept. What exactly don't you understand about it?

I'm more of a "hands-on" math concept guy ... rotational kinematics and torques killed me last chapter ... I don't know what equations to use to set up a problem. Make sense?

I solved for lambda ...

... velocity = (lambda * frequency)

... solving for lambda ...

... lambda = (velocity / frequency) ...

... lambda = ( 343 / 2e4 )

... lambda = .01715m

I know ...

... sin of theta = lambda / D

... therefore, I concluded with ...

... sin of theta = ( .01715 / .072 )

... sin of theta = .238 ...

... but, I'm not trying to find an angle ... am I?

It doesn't seem that I'm looking for an angle ... does anyone else have an idea?

Is there an equation to calculate diffraction?

## What is diffraction?

Diffraction is a phenomenon that occurs when a wave encounters an obstacle or a slit that is comparable in size to its wavelength. This causes the wave to bend and spread out, creating a pattern of interference.

## How is diffraction different from refraction?

Diffraction and refraction are both phenomena that involve the bending of waves, but they differ in their causes. Diffraction is caused by an obstacle or slit, while refraction is caused by a change in the medium the wave travels through.

## What are some common examples of diffraction in everyday life?

Some examples of diffraction in everyday life include the rainbow colors seen when light passes through a prism, the blurry edges of a shadow, and the interference patterns created by ripples in water.

## How is diffraction used in science and technology?

Diffraction is used in various scientific and technological applications, such as X-ray crystallography to determine the structure of molecules, in telescopes to improve resolution of images, and in CD and DVD players to read data.

## What is the difference between diffraction and distraction?

Diffraction and distraction are two different words with distinct meanings. Diffraction refers to the bending of waves, while distraction refers to the act of being pulled away from something or losing focus.

• Introductory Physics Homework Help
Replies
3
Views
2K
• Introductory Physics Homework Help
Replies
2
Views
5K
• Introductory Physics Homework Help
Replies
4
Views
2K
• Introductory Physics Homework Help
Replies
4
Views
3K
• Introductory Physics Homework Help
Replies
4
Views
3K
• Introductory Physics Homework Help
Replies
4
Views
3K
• Introductory Physics Homework Help
Replies
1
Views
6K
• Introductory Physics Homework Help
Replies
2
Views
2K
• Introductory Physics Homework Help
Replies
1
Views
2K
• Introductory Physics Homework Help
Replies
1
Views
3K