[填空题]
Workers around jet ai)eu,x39lc ht vrcraft typically r1yqwl0wa08i wear protective devices over their ears. A0w lr0yiq wa81ssume that the sound level of a jet airplane engine, at a distance of 30 m, is 140 dB, and that the average human ear has an effective radius of 2.0 cm. What would be the power intercepted by an unprotected ear at a distance of 30 m from a jet airplane engine? W
