One day, after pulling down your window shade, you notice that sunlight is passi

Question

One day, after pulling down your window shade, you notice that sunlight is passing through a pinhole in the shade and making a small patch of light on the far wall. Having recently studied optics in your physics class, you're not too surprised to see that the patch of light seems to be a circular diffraction pattern. It appears that the central maximum is about 1 cm across, and you estimate that the distance from the window shade to the wall is about 3 m. Estimate (a) the average wavelength of the sunligh (in nm) and (b) the diameter of the pinhole (in mm).

Note: I've already looked at other answers posted to this question on Chegg. I know how to find the answer to part b) once the answer to part a) is known. However, I have no idea how to figure out a). The only solution to part a) I've seen is to look at graph on a Wiki article. Unfortunately, I cannot just put that as my answer for my homework assignment. So, if anyone can show me how to calculate the average sunlight, that would be amazin!

Explanation / Answer

since central maxima is 1 cm across.
1st minima is at 1/2 = 0.5 cm
use formula of 1st minima:
y = lambda * D/a
Here there are 2 unknown (lambda and a) and cant be calculated.
I dont think they are asking you to calculate lambda by using diffraction. They want to just estimate average wavelength of light which is of yellow color and then apply the above formula to get diameter of pinhole.

Related Questions

Navigate

• Browse (All)
• Browse O
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.