Question

a wave with a period of 0.008 second has a frequency of?

Answer 1

The formula for frequency is f = 1/T where f is frequency and T is period in seconds. 
You have you period which is 0.008s and that is all you will need to solve or frequency in a wave:
f = 1/2
f = 1/0.008s
f = 125Hz

Answer 2

As per the question the time period of the wave is 0.008 s.

we have to calculate the frequency of the wave.

Before going to calculate the frequency of the wave first we have to understand the frequency.

Frequency of a wave is defined as the number of waves passing through  a point in  unit time.

Time period of a wave means time taken by a wave for one complete vibration or oscillation.

The relation between frequency and wave is given as frequency is the reciprocal of time period.

Mathematically we can say $frequency[ f]=\frac{1}{T}$

                                                                       $= \frac{1}{0.008s}$

                                                                         =125 Hz [ans]