Beat Frequency Formula

Sound waves are referred to as the beat. The difference in frequency between two waves is called the beat frequency. Interference, both helpful and detrimental, is to blame. In sound, the beat frequency is defined as the rate at which the loudness of the sound fluctuates, whereas the ordinary frequency of the waves is defined as the pitch of the sound.

Beat Frequency

Beats are created when two waves of almost identical frequencies travelling in the same direction collide at a spot. Whenever two sound waves with different frequencies reach your ear, the opposing productive and harmful disruption enables the sound to alternately be loud and faint. This is known as beating.

Beat frequency is the total value of the frequency difference between the two waves.

Formula

f_b = |f₂ − f₁|

where,

f₁ and f₂ denote the frequency of the two given waves.

Sample Problems

Question 1. Find the beat frequency given the wave frequencies are 550Hz and 380Hz.

Solution:

Given: f1 = 550 Hz and f2 = 380 Hz

Since, fb = |f2 − f1|

= |550 − 390| 

= 210 Hz

Question 2. Find the beat frequency if the wave frequencies are 600 and 420 Hz.

Solution:

Given: f1 = 600 Hz and f2 = 420 Hz

Since, fb = |f2 − f1|

= |600 − 420|

= 180 Hz

Question 3. Find the beat frequency if the wave frequencies are 200 and 920 Hz.

Solution:

Given: f1 = 920 Hz and f2 = 200 Hz

Since, fb = |f2 − f1|

= |920 − 200|

= 720 Hz

Question 4. Find the beat frequency if the wave frequencies are 100 and 210 Hz.

Solution:

Given: f1 = 100 Hz and f2 = 210 Hz

Since, fb = |f2 − f1|

= |100 − 210|

= 110 Hz

Question 5. Find the beat frequency if the wave frequencies are 400 and 760 Hz.

Solution:

Given: f1 = 400 Hz and f2 = 760 Hz

Since, fb = |f2 − f1|

= |400 − 760|

= 360 Hz