Well the answer pops right out of the relation between frequency and period, which is:
f = 1 / T
Where f is frequency and T is period. So what happens when you increase f?
Well let's say that f = 2. So we can find the period when f = 2:
2 = 1 / T, T = 1 / 2
Now what if f = 4?
4 = 1 / T, T = 1 / 4
When f = 2, T = 1/2 and when f = 4, T = 1/4. So what happened when we increased f? T got smaller. So what happens if we decrease f? T gets bigger. Thus the period of a wave increases as its frequency decreases.

Answer #1| 22/12 2013 18:47