# Homework Help: Frequency of a wave?

1. Nov 16, 2006

### jnimagine

i have a question about the frequency of a wave. I thought it was measured in Hz but sometimes in the textbook it said it's measured in
s-1 (-1 in superscript lol)
are they both the same thing?
but in one of the questions it asked to calculate the wavelength in the substance if the frequency is 1000s-1 and the speed of sound in the medium is 1230m/s
If 1000s-1 is the same thing as 1000Hz, why do i get a wrong answer?
I had to use 1000-1 (which is 0.001) to calculate this problem
So what's the difference between the two???

2. Nov 16, 2006

### PhanthomJay

A hertz is a fancy name for 'cycles per second' and has the unit of $$s^{-1}$$. So $$f = 1000Hz = 1000 cycles/sec = 1000s^{-1}$$. In your wavelength problem, you may have transposed the formula. wavelength $$\lamda = v/f =1230/1000 = .001(1230) = 1.2m$$