Geothermal, Wind ,Solar, and Water turbine.
I hope I helped.
I'm assuming it was to keep the data consistent? The further you are from a heat source the less heat will get to you as the temperature tries to reach equilibrium and the waves start to spread out, so you should keep everything the same distance to get consistent results. I don't have any information so this is just my assumption
Answer:
30 m
Explanation:
The wavelength of a wave is found by the velocity divided by the frequency. Therefore, the wavelength is (300 m/s)/(10 Hz) = 30 m
I hope this helps! :)