Answer:
[tex]f_{beat} = 8.1 Hz[/tex]
Explanation:
Wavelength of sound produced is given as
[tex]\lambda_1 = 6m[/tex]
[tex]\lambda_2 = 7m[/tex]
now we know that the frequency of sound is given as
[tex]f_1 = \frac{c}{\lambda_1}[/tex]
[tex]f_1 = \frac{340}{6} = 56.67 Hz[/tex]
frequency of the other sound is given as
[tex]f_2 = \frac{c}{\lambda_2}[/tex]
[tex]f_2 = \frac{340}{7} = 48.57 Hz[/tex]
now the beat frequency is given as the difference of the frequency
[tex]f_{beat} = f_1 - f_2[/tex]
[tex]f_{beat} = 56.67 - 48.57[/tex]
[tex]f_{beat} = 8.1 Hz[/tex]