16.11 Energy in Waves: Intensity

Which measurement of a wave is most important when determining the wave's intensity?

Ultrasound of intensity $1 . \text{50} \times \text{10}^{2} \text{W}/\text{m}^{2}$ is produced by the rectangular head of a medical imaging device measuring 3.00 by 5.00 cm. What is its power output?

To increase intensity of a wave by a factor of 50, by what factor should the amplitude be increased?

Energy from the Sun arrives at the top of the Earth’s atmosphere with an intensity of $1.30 \text{ kW}/\text{m }^{2} .$ How long does it take for $1.8 \times 10^{9} \text{J }$ to arrive on an area of $1 .\text{ } 00 \text{m }^{2}$?

Suppose you have a device that extracts energy from ocean breakers in direct proportion to their intensity. If the device produces 10.0 kW of power on a day when the breakers are 1.20 m high, how much will it produce when they are 0.600 m high?

A microphone receiving a pure sound tone feeds an oscilloscope, producing a wave on its screen. If the sound intensity is originally $\text{2}.\text{00 } \times \text{10}^{–\text{5}} \text{W}/\text{m }^{2} ,$ but is turned up until the amplitude increases by 30.0%, what is the new intensity?