Question 499: Waves

Question

Two sources of sound placed close to each other, are emitting progressive waves given by 
y1 = 4sin600$$\pi $$t  and  y2 = 5sin608$$\pi $$t
An observer located near these two sources of sound will hear

Accepted Answer

$$2\pi {f_1} = 600\pi $$
$${f_1} = 300$$   ...(i)
$$2\pi {f_2} = 608\pi $$
$${f_2} = 304$$   ...(ii)
$$\left| {{f_1} - {f_2}} \right| = 4\,beats$$
$${{{I_{\max }}} \over {{I_{m.n}}}} = {{{{\left( {{A_1} + {A_2}} \right)}^2}} \over {{{\left( {{A_1} + {A_2}} \right)}^2}}} = {{{{\left( {5 + 4} \right)}^2}} \over {{{\left( {5 - 4} \right)}^2}}} = {{81} \over 1}$$
where A
1
, A
2
are amplitudes of given two sound wave.

Answer

4 beats per second with intensity ratio 25 : 16 between waxing and waning.

Answer

8 beats per second with intensity ratio 25 : 16 between waxing and waning.

Answer

8 beats per second with intensity ratio 81 : 1 between waxing and  warning.

Answer

4 beats per second with  intensity ratio 81 : 1 between waxing and waning.

Waves

Two sources of sound placed close to each other, are emitting progressive waves given by y1 = 4sin600$\pi t and y2 = 5sin608\pi $t An observer located near these two sources of sound will hear

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