Answers to Decibel Problems 10–113

10. Two tones, each of 50 Hz, have intensity levels of 50 dB and 120 dB, respectively. What is the loudness level of each in phons? (Refer to the equal-loudness curves above.)

Answer: 15 phons and 110 phons.

11. Three tones of 50 Hz, 1,000 Hz, and 5,000 Hz each have a loudness level of 60 phons. What is the intensity level in dB of each?

Answer: 78 dB, 60 dB. and 53 dB.

12. A 100-Hz tone of intensity level 50 dB is about as loud as a 1000-Hz tone of intensity level 40 dB. (You can see this relationship by examining the equal-loudness curves above). What is the ratio of the intensity of the 100-Hz tone to that of the 1,000-Hz tone?

Answer: 10.

13. What is the intensity level of a 50-Hz tone that sounds as loud as a 5,000-Hz tone of intensity level 40 dB?

Answer: 69 dB.

2013 Robert Chuckrow

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