Sound will travel fastest in air at . -5°C
0°C
10°C
15°C
The following table lists the speed of sound in various materials. Use this table to answer the question.
Substance
Speed (m/s)
Glass
5,200
Aluminum
5,100
Iron
4,500
Copper
3,500
Salt water
1,530
Fresh water
1,500
Mercury
1,400
Hydrogen at 0°C
1,284
Ethyl Alcohol
1,125
Helium at 0°C
965
Air at 100°C
387
Air at 0°C
331
Oxygen at 0°C
316

When a vertical beam of light passes through a transparent medium, the rate at which its intensity i decreases is proportional to i(t), where t represents the thickness of the medium (in feet). in clear seawater, the intensity 3 feet below the surface is 25% of the initial intensity i0 of the incident beam. what is the intensity of the beam "10" feet below the surface? (give your answer in terms of i0. round any constants or coefficients to five decimal places.)