Question

The number of beats per second resulting from the vibrations $x_1=acos500\pi t$ and $x_2=acos508\pi t$ is

• A. Zero
• B. 2
• C. 4
• D. 8

Answer 1

The correct option is C 4

Given, two equation $y=a\cos \left(500\pi t\right)\&y=a\cos \left(508\pi t\right)$

Comparing to a standard equation :

$y=a\cos \left(\omega t\right)$

We get , ${\omega }_1=500\pi t\&{\omega }_2=508\pi t\Rightarrow f_1=250Hz\&f_2=254Hz$

So, $f_{beat}=f_2-f_1=4Hz$

So, C is the correct answer.