00:01
Hi there, so for this problem we are asked about what is the approximate size of the smallest object on the earth that astronauts can resolve by eye when they are orbiting 250 kilometers above the earth? so let's call this the distance l, which is 250 kilometers.
00:29
That is the same as 250 times 10 to the 3 meters.
00:40
And we need to assume that the wavelength is given, and that wavelength is equal to 626 nanometers.
00:54
That means 626 times 10 to the minus 9 meters.
01:06
And we are also told that a pupil diameter is also given.
01:12
So let's call this the diameter d, which is equal to 5 .10 millimeters, which is 5 .10 times 10 to the minus 3 meters.
01:30
We know that when the pupil is open wide, it appears that the resolving power of human vision is limited by the coarseness of light sensors on the retina.
01:43
But we use ryle's criterion as a healthy indicator of how good our vision might be.
01:51
So with the values that we are given, we know that the smallest object that the astronaut can resolve is given by ryle's criterion...