Question

In Bob Shaw's short story, "The Light of Other Days," he describes something called slow glass. In the story, a married couple buys a 4-foot-wide window of slow glass that has been out on a beautiful hillside in Ireland, collecting light for 10 years. The idea is that the light takes 10 years to pass through the glass, so if you mount the window in your house it will give a view of the Irish landscape for the next 10 years, slowly unveiling everything that happened there. You can read the full short story via the link below, if you are interested.

Link to Bob Shaw's short story: The Light of Other Days.

(a) In the short story, the couple buys a window that is one-quarter-inch thick, and takes light 10 years to pass through. Let's say that you were able to locate a supplier of slow glass, and you bought some glass that was 5.00 mm thick, with the light taking 7.00 years to pass through. Taking one year to be 365.24 days, calculate the index of refraction of your piece of slow glass.

In 1999, Lene Hau, a physicist at Harvard University, received quite a bit of attention for getting light to travel at bicycle speed (later, she was able to temporarily stop light completely). The speed of a bicycle is a lot faster than light travels through the slow glass from the story, but it is still orders of magnitude less than the speed at which light travels through vacuum. If you're interested, you can follow this link to learn more about Lene Hau.

(b) Lene Hau used something called a Bose-Einstein condensate to slow down light. If the light is traveling at a speed of 40.0 km/hr through the Bose-Einstein condensate, what is the effective index of refraction of the condensate?

Answer 1

Consider the following calculations

Step-by-step explanation:

a ) velocity of the glass is v = distance / time

= 5 X 10-3 / 7 X 365.24 X 24 X 60 X 60

v = 2.263 X 10-11 m/sec

the speed of the light in vaccum is C

C = 3 X 108 m/sec

n = C / v

n = 3 X 108 / 2.263 X 10-11

n = 1.32567 X 1019

b ) given is 40 km/hr

= 40 X 103 / 60 X 60

= 11.11 m/sec

n = C / v

n = 3 X 108 / 11.11

n = 27002700.27