A una distancia de 12.0 m dsde una fuente puntual, el nivel de intensidad es de 70dB. A que distancia desde la fuente el nivel de intensidad sera de 40dB.

I'm thinking it's 2 you are asked to explain the earth's magnetic field. which is the best reply? 1. the earth's magnetic south is similar to the north pole of a magnet. 2. the earth's core has a strong magnetic charge similar to the south pole of a magnet. 3. the earth's geomagnetic south is similar to the south pole of a magnet. 4. the earth's magnetic charge is not centered at either pole; it varies based on location.