A point source of sound has a power of 15 W15\text{ W}15 W. Calculate, in dB\text{dB}dB, the intensity level at a distance of 8.0 m8.0\text{ m}8.0 m from the source. The threshold of hearing is I0=1.0×10−12 W m−2I_0 = 1.0 \times 10^{-12}\text{ W m}^{-2}I0=1.0×10−12 W m−2.
The frequency of a sound is increased from 1.0 kHz1.0\text{ kHz}1.0 kHz to 3.0 kHz3.0\text{ kHz}3.0 kHz with no change in intensity. One change in the sound perceived by a person with normal hearing is an increase in pitch. Explain one other change to the sound perceived by the person as the frequency is increased from 1.0 kHz1.0\text{ kHz}1.0 kHz.
