A man on a beach notices that four waves arrive on the shore every 20 seconds. What is the frequency of the waves?

0.2 Hz

Explanation:

Frequency: This can be defined as the number of circles completed by a wave in one seconds. The s.i unit is hertz.

From the question,

If 4 Waves arrives on the shore every 20 seconds,

Then,

x waves will arrives on the shore in one seconds

Solving for x

x = (4×1)/20

x = 0.2 Hz

Hence the frequency of the wave is 0.2 Hz

the answer is ampere

the ampere is used to measure electricity. an ampere is a unit of electric current equal. a unit of measure for the flow of current in a circuit. one ampere is the amount of current flow provided when one volt of electrical pressure is applied against one ohm of resistance.