Wave equations

Question 1

How do you find wave speed/velocity using:

a) speed, frequency and wavelength
b) speed, distance, and time

Answer 1

a) v = f x λ

v = wavelength, m/s
f = frequency, Hz
λ = wavelength, m

b) v = x/t

x = distance, m
t = time, s

Question 2

A seismic wave has a frequency of 15 Hz and travels at 4050 m/s.

Calculate its wavelength.

Answer 2

v = fλ
λ = v/f

4050/15 = 270m

Question 3

A wave on the sea is travelling at 4 m/s.

Calculate how long it takes to travel along a 20m long pier.

Answer 3

v = x/t
t = x/v

20/4 = 5s

Question 4

A sound wave with a frequency of 100 Hz has a speed of 330 m/s.

Calculate its wavelength.

Answer 4

v = fλ
λ = v/f

= 330/100 = 3.3 m

Question 5

A wave in the sea travels at 25 m/s.

Calculate the distance it travels in one minute.

Answer 5

1 minute = 60 s
v = x/t
x = vt

= 25 x 60 = 1500 m