Diffraction Problem, Calculate Slit Width

In summary, to calculate the slit width based on the given information, you need to use the formula sin theta = m*lambda/a, where theta is the angle between the central maximum and the first minimum, m is the order of the minimum (in this case, m=1), lambda is the wavelength of light, and a is the slit width. By rearranging the formula, you can solve for a, which comes out to be approximately 6.8*10^-5 m.
  • #1
TheRedDevil18
408
1

Homework Statement



Light of wavelength 680nm falls onto a single slit. The diffraction pattern is observed on a screen 50cm away. If the distance between the first and the third minima is 3mm, calculate the slit width?


Homework Equations



sin thetha = m*lambda/a
y = m*lambda*R/a

The Attempt at a Solution



So the distance between the first position and last position of the dark band is 3mm?

I think this is wrong:

3*10^-3 = (3)(680*10^-9)(0.5)/a
a = 3.4*10^-4 m
 
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  • #2
TheRedDevil18 said:

Homework Equations



sin thetha = m*lambda/a
y = m*lambda*R/a

The Attempt at a Solution



So the distance between the first position and last position of the dark band is 3mm?

I think this is wrong:

3*10^-3 = (3)(680*10^-9)(0.5)/a
a = 3.4*10^-4 m

There are a couple of issues with your attempt.

1. It looks like you have inserted an extra factor of 0.5 for no apparent reason.

2. Without the 0.5, the formula gives the spacing between the 3rd minimum and the central maximum.
However, the 3 mm given in the problem statement refers to the spacing between the 3rd minimum and the 1st minimum. So you need to bring the 1st minimum (n=1) into the picture.
 

1. What is diffraction and why is it important?

Diffraction is the bending or spreading of waves as they pass through an opening or around an obstacle. It is important because it allows us to understand the properties of light and other forms of waves, and it has many practical applications in fields such as optics, acoustics, and radio technology.

2. How does diffraction relate to calculating slit width?

In the context of calculating slit width, diffraction refers to the phenomenon of light waves spreading out as they pass through a narrow slit. By understanding the principles of diffraction, we can determine the necessary slit width for a given wavelength of light to produce a desired diffraction pattern.

3. What factors affect the diffraction pattern and the calculation of slit width?

The main factors that affect the diffraction pattern and the calculation of slit width are the wavelength of the light, the size of the slit, and the distance between the slit and the screen where the pattern is observed. The shape and angle of the incident light also play a role.

4. How do you calculate the slit width for a specific diffraction pattern?

The calculation of slit width involves using the properties of waves and the principles of diffraction. The equations used depend on the specific diffraction pattern desired, such as single-slit, double-slit, or multiple-slit patterns. Generally, the slit width can be calculated using the wavelength of the light, the distance between the slit and the screen, and the desired width of the central maximum of the pattern.

5. What are some real-world applications of calculating slit width in diffraction problems?

There are many real-world applications of calculating slit width in diffraction problems. For example, in the field of optics, knowing the necessary slit width can help design lenses, telescopes, and other optical instruments. In radio technology, calculating slit width is important for designing antennas and improving signal quality. It is also used in the study of crystal structures and in medical imaging techniques such as X-rays and ultrasound.

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