Question 18.96

66. Unit conversion can matter, and the number of significant digits in the conversion factor can matter. New electronic components are designed using metric units, but accompanying circuit boards are often designed using U.S. customary units. Consider a connector with 100 pins on a side with design distance (“pitch”) of 0.6 mm from one pin to the next. (Thanks for the idea to Mark Biegert, Calix, Inc., Plymouth, Minnesota.)

  1. How far, in mm, is the 100 th pin from the first one?
  2. Use the conversion factor in., which is accurate to five decimal places and four significant digits, to calculate the distance in inches of the 100th pin from the first one. Then convert that quantity back to millimeters by using the exact conversion .
  3. Use the conversion factor in., which is accurate to three decimal places but only two significant digits, to calculate the distance of the 100th pin from the first one. Then convert that quantity back to millimeters by using the exact conversion . Will that last pin fit into a slot that is the exact distance of mm from the first pin?