An observer notices that 12 waves pass by in 4 seconds. What is the frequency of these waves? 0.33 Hz 16 Hz 48 Hz 3 Hz

Frequency = 3 Hz

Explanation:

Frequency is a measure of Hertz. Recall that Hertz is the unit expressing cycles/second, where one second is the denominator of the fraction for simplicity. If there are 12 waves every four seconds, and one wave represents one cycle, dividing 12 waves by 4 seconds will give the answer of 3 waves (or cycles) per one second.