A loudspeaker has a circular opening with a radius of 0.1158 m. The electrical power needed to operate the speaker is 27.0 W. The average sound intensity at the opening is 25.6 W/m2. What percentage of the electrical power is converted by the speaker into sound power

electrical power is converted by the speaker into sound power 17.25 %

Explanation:

given data

radius = 0.1158 m

power needed = 27.0 W

average sound intensity = 25.6 W/m²

solution

we know sound intensity that is

I =   ...................1

power = intensity × area

Power = 25.6 × 4 ×π×r²

Power = 25.6 × 4 ×π×0.1158²

power = 4.313 W

so here electric power % into sound power

= × 100

= 17.25 %

electromagnetic shielding is the practice of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. shielding is typically applied to enclosures to isolate electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. electromagnetic shielding that blocks radio frequency electromagnetic radiation is also known as rf shielding.

the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia