Intensity of Sound: A certain factory whistle can be heard up to a distance of 9.8 km. Assuming that the acoustic output of the whistle is uniform in all directions, at what distance from the factory is the intensity level of the whistle sound equal to 25 dB? The threshold of human hearing is 1.0 × 10-12 W/m2.
A. 550 m
B. 660 m
C. 830 m
D. 940 m
E. 1100 m
Answer: A
You might also like to view...
Density is calculated as
A. mass times volume. B. volume divided by mass. C. mass divided by volume. D. mass times gravity.
Which of the following statements cannot be tested by science today?
A) Prior to the Planck time, our universe sprouted from another universe. B) Our universe is flat. C) The universe is 14 billion years old. D) The expansion of the universe is now accelerating.
The energy transformed in an inductor during a portion of a cycle
A) is always positive. B) may be positive, negative, or zero. C) is always negative. D) is always zero. E) is never zero.
Which of the following statements is true of interstellar dust?
A) It makes up about 10 percent of the mass of the interstellar medium. B) The average size of particles of interstellar dust is 1 micrometer. C) It is made mostly of carbon and silicates mixed with frozen water. D) It is uniformly distributed through space.