00:01
Part a of this problem is asking for the wavelength of this wave.
00:05
And so we can get that by doing the speed of the wave over the frequency of the wave.
00:11
And so the speed of the wave is 3 times 10 to the 8 meters per second.
00:16
It's just the speed of light.
00:18
And then the frequency is given to us as 8 .3 times 10 to the 5th.
00:22
And the units are hertz.
00:26
And so doing this out gives us a value of 361 meters.
00:35
Part b is asking for the wave number.
00:38
So the definition of the wave number is 2 pi over the wavelength.
00:43
And so playing the wavelength they give us, actually we calculate it here, so they don't give it to us, we get it in part a.
00:50
So it's 2 pi over 361.
00:54
And this gives us 0 .0174.
00:57
And the units are radians per meter...