3.2 The adjustable mirror in a Michelson interferometer is moved a distance of 0.223 mm and 769 bright fringes cross the field of
view of the telescope. What is the wavelength of light that is being used?
m3.3 A standard helium-neon laser has a wavelength of 633 nm, and is used in a Michelson interferometer experiment. If the
adjustable mirror is moved a distance of 0.0216 mm, how many bright fringes cross the field of view of the telescope?
fringes3.4 The textbook speaks of moving the adjustable mirror in a Michelson interferometer by as little as a quarter wavelength of
light, using a "finely threaded screw adjustment." This is an interesting claim: Just how finely threaded does such an
adjustment screw have to be? Assume that the screw can be turned by as little as one-quarter of a degree with fair accuracy.
How many screw threads must there be in each millimeter of the screw's length in order for a turn of one-quarter degree to
advance the screw by 125 nm, a quarter of a wavelength of blue light? State your answer to the nearest hundredth. Hint: The
pitch of any screw is defined as the distance between adjacent threads, or equivalently, the distance the screw advances after
one full turn, 360°.
threads/mm