00:01
In this question, i'm using this equation that relates the diffraction angle to the wave links of the sound and the diameter of the speaker.
00:12
And this equation for ideal gas that is relating the speed of sound to the temperature.
00:20
So we have a sound with frequency 3 kilohertz or 3 ,000 hertz.
00:28
The diameter is 0 .175 meters.
00:34
And we want to find a diffraction angle at two temperatures, 0 celsius or 273 kelvin, and t2 29 celsius or 302 kelvin.
00:51
Okay.
00:53
So at 0 degrees, we know that the speed of sound is 331 meter per second.
01:06
So here i can find sign of theta equal to 1 .22 v over f times d.
01:19
So we know that lambda is v over f and then i can say sign of theta is equal to 1 .22, 331 meter per second over 3 ,000 hertz times 0 .175 meters.
01:47
So keta is sine inverse of all this 331 meter per second divided by 3 ,000 hertz, and times 0 .175 meters, and this would be equal to 50 .3 degrees.
02:20
Okay.
02:21
But to find a theta or diffraction angle at 302 kelvin, we need to find the speed of sound at that temperature...