Question

A blind is pulled down to cover a window but it has a pinhole in it that is allowing sun to enter the room. On a wall that is 2.30 m away you can see a circular diffraction pattern from the pinhole. The central maximum of this circular diffraction has a diameter of 0.900 cm. What is the diameter of the pinhole?

(Hint: Estimate the average wavelength of the sunlight first.)

Answer 1