Map h sapling learning You find an unlabeled box of fine needles, and want to de

Question

Map h sapling learning You find an unlabeled box of fine needles, and want to determine how thick they are. A standard ruler won't do the job, since all you can tell is that each needle is less than a millimeter thick. So to find the thickness, you use the needle to poke a hole in a piece of brown construction paper. Then you arrange your 640 nm laser pointer to shine through the hole, and a circular diffraction pattern, consisting of a central bright circle surrounded by alternating dark and bright rings, appears on the wall 23.2 m away. Now you can use your ruler to measure that the central bright círcle is 12.7 cm in diameter. What is the diameter of the needle? otheanedie youler to measure that the central bright circle is 12.7 cm in diameter. What is the diameter Number

Explanation / Answer

using diffraction for a circ aperture

1.22 * wavelength = D y / L

1.22 * 640 = D * (0.172 / 2) / 23.2

D = 210634 nm = 211 um is the diam of the needle

Related Questions

Navigate

• Browse (All)
• Browse M
• Subjects

---