Learn about how waves are measured according to amplitude, wavelength and frequency.

Part of

The frequency of a wave can also be calculated using this equation:

where:

f = frequency = number of waves produced by a source per second, in hertz Hz.

T = period = time it takes for one complete vibration or oscillation, in seconds s.

A sound wave has a time period of 0.0001 seconds. What is its frequency?

**Answer**

f = 10,000 Hz

The frequency of the sound wave is 10,000 Hz.

- Question
A radio wave has a frequency of 3 MHz. What is its period?

f = 3 MHz = 3 x 10

^{6}HzT = 0.00000033 s

T = 0.33 x 10

^{-6}= 0.33 μsThe period of the radio wave is 0.33 μs

- Question
A boat at sea bobs up and down as waves pass. The vertical distance between a crest and a trough is 52 cm and 20 waves pass the boat in 30 seconds.

- What is the amplitude of the waves?
- What is the frequency of the waves?

1. The amplitude of a wave is the maximum displacement of a point of a wave from its rest position. This is exactly half the distance between a crest and trough.

The distance between a crest and trough = 52 cm.

= = 26 cm.

The amplitude of the wave is 26 cm.

2.

number of waves = 20

time taken = 30 s

f = 0.67 Hz

The frequency of the waves is 0.67 Hz.