00:01
So we have a sheet of ice, which is two centimeters thick, and then underneath there's a sheet of quartz, which is 1 .1 centimeters long, white.
00:17
So light comes in through here, travels through here, travels through here, we have to find the time it takes to go through the ice, and then we need to find the time it takes to go through the quartz.
00:30
But before we do that we need to be able to find the speed so for ice we have the refractive index is equal to speed of light in vacuum divided by speed of light in the medium so v is equal to c over n which is equal to 3 .0 times 10 to the power 8 divided by the refractive index of glass of ice which is 1 .309 so that gives me speed of light in ice would be 2 .29 times 10 to the power 8 meter per second.
01:09
And that means that the time that the light travels through ice would be equal to the distance travel through the ice divided by the speed 2 .29 times 10 to the power 8.
01:21
So that time is equal to 8 .73 times 10 to the negative 11 second.
01:29
And then we'll do the same.
01:31
Same thing for quartz.
01:33
So for quartz, we first find the speed...