Annual salary(2012) = $70,000
Annual inflation = 7%
Therefore, the salary you need to earn in 2020 in order to have the same purchasing power can be calculated below


where
n = 8
r = 7/100 = 0.07
PV = 70, 000

The salary you need to earn in 2020 to have the same purchasing power = $120, 273.03
The correct options are:
D
"Radio waves have a lower frequency, which makes them safer for humans."
B
"Radio waves take less energy to produce."
<h3>
Why do we radio waves over other electromagnetic waves to transmit information to Earth? </h3>
Radio waves are electromagnetic waves with frequencies on the range from 10 KHz to 10 THz.
Now, remember that all electromagnetic waves have the same speed, which is the speed of light, and the energy of a wave is proportional to its frequency.
Particularly, we can see that radio waves have small frequencies (smaller than infrared light) so these waves carry very little energy.
With that in mind, the correct options are.
D
"Radio waves have a lower frequency, which makes them safer for humans."
B
"Radio waves take less energy to produce."
These are the two main reasons of why we use radio waves.
If you want to learn more about electromagnetic waves.
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Answer:
A blackbody, or Planckian radiator, is a cavity within a heated material from which heat cannot escape. No matter what the material, the walls of the cavity exhibit a characteristic spectral emission, which is a function of its temperature.
Example:
Emission from a blackbody is temperature dependent and at high temperature, a blackbody will emit a spectrum of photon energies that span the visible range, and therefore it will appear white. The Sun is an example of a high-temperature blackbody.
<span>A. three</span><span>
Oil spill can be very harmful to marine life because the chemical make up of oils can be poisonous to marine life. The oil can also affect the natural body temperature of marine animals especially to the small fish. Sea otters and sea birds are the most commonly affected by oil spills and those other marine animals that can be found in the shoreline. Heavy oils like the bunker oils used to fuel ships are the most harmful oil because when this oil stick to birds feathers, they may have an inability to warm themselves that could lead them to die.</span>
Answer:
The Michelson-Morley was designed to detect the motion of the earth through the ether.
No such relation was found and the speed of light is assumed to be the same in all reference frames.