Question

9) A loudspeaker is supplied with 5.0 W of electrical power and has an efficiency of 10% for converting this electrical power to sound power.

At a distance of 4.0 m, the sound intensity = ___W/m^2.

Answer 1

Let us assume that the loud speaker radiates the sound radially. Then the sound intensity of the loud speaker is given by electrical power multiplied by its efficiency, while divided by 4πr^2 , because it is assumed to be radially emitting in all directions. Then the sound intensity is :

Sound Sound Interesting conten effistency 4 X2 - electric Power n = 0.1 [:: 107.3 . I = 5W xo. 0.5 W = 4 T (4m) 2 m)2 4 (3.14) 16 m2 = 0.00248 W/m² I = 2.48 x 10-3 W/m2 2.48 X I

Hence the sound intensity deliverd is 0.00248 watt/m^2 .

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