2. The intensity level 15.0 m from a speaker is 85 db. What acoustical power would pass through a rectangular window (2.0 m x 1.0 m) in a wall at this distance from the speaker? Assume that the speaker is a point source radiating in all directions. (A) 6.32 x 104 W (B) 7.98 x 104 W (C) 4.85 x 104 W 1.36 x 10-5 W (E) 1.78 x 10-5 W 3. A 2.0 m long piano string on a piano normally has a primary resonance at 440 Hz, but is out of tune. A piano tuner hears a beat frequency of 5 Hz when a 440 Hz tuning fork is sounded near the string and a beat frequency of 5 Hz when a 450 Hz tuning fork is sounded near the string. Which one of the following statements is true? (A) (B) (C) (D) (E) The first harmonic of the piano string has a frequency of 435 Hz. The second harmonic of the piano string has a frequency of 890 Hz Shortening the string by the right amount will tune its frequency to 440 Hz. Increasing the tension (and wave velocity) on the string will tune it to 440 Hz None of the above statements is true.

2. The intensity level 15.0 m from a speaker is 85 db. What acoustical power would pass through a rectangular window (2.0 m x 1.0 m) in a wall at this distance from the speaker? Assume that the speaker is a point source radiating in all directions. (A) 6.32 x 104 W (B) 7.98 x 104 W (C) 4.85 x 104 W 1.36 x 10-5 W (E) 1.78 x 10-5 W 3. A 2.0 m long piano string on a piano normally has a primary resonance at 440 Hz, but is out of tune. A piano tuner hears a beat frequency of 5 Hz when a 440 Hz tuning fork is sounded near the string and a beat frequency of 5 Hz when a 450 Hz tuning fork is sounded near the string. Which one of the following statements is true? (A) (B) (C) (D) (E) The first harmonic of the piano string has a frequency of 435 Hz. The second harmonic of the piano string has a frequency of 890 Hz Shortening the string by the right amount will tune its frequency to 440 Hz. Increasing the tension (and wave velocity) on the string will tune it to 440 Hz None of the above statements is true.