00:01
Now here in this class, you look at light going through a window, right? suppose your window has, you know, has, it's made of glasses, right? and i think, for example, for my window, the glass is of a thickness less, the d is about, i think it's about maybe two centimeters, okay? that's pretty thick enough.
00:20
And the light comes in and the path through, right? and because it goes through the wind glass, so the time, i mean, because the speed of light in the wind glass actually is lower than in the vacuum.
00:36
So at the time, the time it takes for the light to go through actually similar thickness.
00:44
It's actually longer, right? so there's a time delay there.
00:47
And of course, the time delayed, you can easily work it out, right? that d over c sees the speed of light in a vacuum, right? that's, of course, given by three times 10 centimeter per second, right? in vacuum, right? so minus, of course, d over, you know, c over the reflective index, n, right? so the reflective index for a glass, i call it n, and c over n is this bit of light in the glass, right? so, and, you know, n is roughly about 1 .4 for most glasses, right? for thica, for example.
01:22
So, and this is a time delay, right? and of course, if you put in the values, you found this to be actually something like d over c over 1 minus n, right? and that of course gives you basically, if you look at the time delay and neglect the sign, and of course that it gives you 0 .4 times d over c, right? so if you work it out, that's given by 2 over 3 times 10 to 10 second, right? so this is extremely small number, as you can see.
01:57
So actually 0 .8 divided by 3, that gives you something like 0 .8 divided by 3, and you'll find this to be 2 .266.
02:08
So i would get it to be 2 .6, something like 2 .6 or 2 .67 times 10 to minus 11 seconds.
02:19
So this is roughly about 26 .7 pique a second.
02:25
It's extremely.
02:27
Small delay, right? and of course, you can work out how many wavelengths is it delayed, right? the wavelengths, the number of wavelengths, the number of wavelengths, the number of wavelengths is delayed, of course, is basically given by, of course, this time, right? so that's 26 .7 pica second divided by, and of course, the frequency of light.
02:53
The frequency of light, you know, is, it depends on the, it really depends on the, how to say, the frequency of the light, right? it depends on the, actually, the frequency of the light.
03:05
So you did not, the question did not give you a frequency of light, but actually know that the frequency of the light, it's basically given by the speed of light times the wave number...