Intensity = power /area in Watts/meter 2 (area = 4 x r if r is the distance from the source) power = energy/ time (Watts =]/second) Intensity and distance from source: I1 ri = 12 rz Sound Level (decibel dB) = 10 * log (-); where Io = 10-12W/m 1. A wave with 20W power is incident on a 2m area. What is the intensity at that area? I = W/m- 2 A wave carries 50J of energy in 2 seconds. What is its power? 3. If the intensity of a wave is 0.034 W/m at a distance of 5m from the source, then what is its intensity Im from the source? 12 = 4.If the intensity of a wave is 3.5 W/m at a distance of 2m from the source, then what is its intensity 5m from the source? I2 = 5. If the intensity of a wave is 0.080 W/m- at a distance of 5m from the source, then at what distance from the source will the intensity be 0.020 W/m-? r2 = m 6. The intensity of sound at a point is 4.6 x 108 W/m?. What is this in decibels? dB 7. The intensity of sound at a point is 8.6 x 10-l' W/m. What is this in decibels? dB 8. The intensity of sound at a point is 3.2 x 10" W/m . What is this in decibels? dB