Finding distance between two slits in conditions related to Young's Experiment

[wScott]

Good evening to all you genius people out there, I've been racking my brains for the past 10 minutes and can't come up with anything.

The exact wording of the question:

Describe how you could use light of a known wavelength to find the distance between two slits.

I thought of using distance = wavelength/ sin(theta). But then I realized I'm not given the angle. Got any suggestions for this predicament?

 

[physics girl phd]

Hint -- Do you know what the "far field" pattern looks like when you send monochromatic (and coherent) light through two neighboring slits? the angle will come from something about that.

 

[kyle8921]

I would suggest using the equation d = mλ/Δy, where d is the distance between the two slits, m is the order of the interference pattern, λ is the wavelength of the light, and Δy is the distance between consecutive bright fringes. This equation is derived from the concept of constructive interference in Young's experiment.

To find the distance between the two slits, you can first place a screen at a known distance from the slits and observe the interference pattern. By measuring the distance between consecutive bright fringes on the screen (Δy) and knowing the order of the fringe (m), you can solve for the distance between the slits (d). This method does not require the measurement of the angle and can be easily performed with a ruler or caliper.

Another method could be using a diffraction grating instead of two slits. A diffraction grating is a device that contains multiple parallel slits with a known distance between them. By shining a light of known wavelength through the grating, you can measure the angle at which the bright fringes appear and use the equation d = mλ/sin(theta) to find the distance between the slits. This method is more accurate and precise, but it requires specialized equipment.

In conclusion, there are various methods to find the distance between two slits in Young's experiment. By using the equations and principles of interference and diffraction, we can accurately determine this distance and further understand the behavior of light. Keep up the good thinking and keep exploring the wonders of science!