The speed of sound in dry air at 20 °C is 343 m/s and the lowest frequency sound wave that the human ear can detect is approximately 20 Hz. (a) What is the wavelength of such a sound wave?

Video transcript

Hey everyone in this example we need to calculate wavelength of the sound that has a frequency of 44.5 hertz and travels with a speed of 351. m per second at 35 degrees Celsius. So we're going to recall that our formula for wavelength is equal to our speed of light, divided by our frequency. We should recall that frequency can be in units of hertz Or inverse seconds which are equivalent. And so from the prompt were given a frequency equal to a value of 44.5 Hz, which we can say is equal to 44.5 inverse seconds. And sorry, that should all be visible here. So solving for our wavelength, we would get that our speed which we won't plug in the variable for speed of light. We're actually going to plug in the speed given in the prompt As 351. m/s. This is divided by our frequency, which we said is equivalent to inverse seconds. And from the prompt were given 44.5 hertz equivalent to inverse seconds. So we divide by that in our denominator. And what we're going to get is a value for frequency equal to 7.91. And then as far as our units will be able to cancel out seconds with inverse seconds. Leaving us with meters as our unit for frequency. So we would have 7.91 m as our wavelength to complete this example. So this is our final answer for wavelength. If you have any questions, please leave this or please leave them down below, and I will see everyone in the next practice video.