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 2 cmcm across, and you estimate that the distance from the window shade to the wall is about 5 mm.

Required:
Estimate the diameter of the pinhole.

Complete 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 2 cm across, and you estimate that the distance from the window shade to the wall is about 5 m.

Required:

Estimate the diameter of the pinhole.  

The diameter is  

Explanation:

     From the question we are told that

            The central maxima is

            The distance from the window shade is

     The  average wavelength of the  sun is mathematically evaluated as

 Generally the visible light spectrum  has a wavelength  range  between  400 nm  to 700 nm  

        So  the initial wavelength of the sun is

           and the final wavelength is  

  Substituting this into the above equation

The diameter is evaluated as

substituting values

answer: a. same unit

explanation:

option number c is the right answer.