Physics Question

Question

Two horns emit frequencies of 110 hz. and 140 hz. (a.) What is the difference in their wavelengths if the air temp. is 10.0 C.? (b.) what beat freq. will be heard?

Answer 1

Hi Grace!

 

Part(a)  deals first with the formula for the speed of sound in air as a function of temperature (in Celsius).  I usually see that as:

 

v ≅ (331.4+0.6T_c) m/s

 

where T_c = temperature in Celsius

 

Once you have that speed, you can use:

 

v = fλ

 

to solve for the wavelengths corresponding to those frequencies.

 

For Part (b), the beat frequency generated by two frequencies is just the absolute value of the difference between them (it is, in fact, sometimes called the "difference frequency").

 

Hope that helps!  Let me know if you have more questions, or would like to check an answer.