If sunlight shines straight onto a peacock feather, the feather appears bright blue when viewed from 15 on either side of the incident beam of light. The blue color is due to diffraction from parallel rods of melanin in the feather barbules, as was shown in the photograph on page 940. Other wavelengths in the incident light are diffracted at different angles, leaving only the blue light to be seen. The average wavelength of blue light is 470 nm. Assuming this to be the first-order diffraction, what is the spacing of the melanin rods in the feather?
PHYS 1010 Notes Week 12 April 48 General theory of relativity Covers accelerating and nonaccelerating reference frames You can always tell if you are accelerating by dropping an object and watching it move, but we can't distinguish between an accelerating reference frame and gravity Airplanes travel in curved paths because they take the shortest route possible. They fly closer to the North or South Pole and then back down because the earth is smaller further from the equator Light can travel in a curved path because space itself is curved; on a curved surface, the fastest path is curved So, gravity exists because mass curves space Mass creates an indentation in spacetime, which explains the attra
