Answer:
The answer to your question is: 20
Explanation:
Atomic number is the number of proton and atom has. Each element has a specific number of protons, if the number of protons change, then this is a new element.
Mass number is the number of protons and neutrons and atom has.
Mass number = protons + neutrons
Data
Number of protons = ?
Atomic number = 20
Then,
atomic number = number of protons = 20
Answer:
There are layers on the Earth. There is gas on the Sun.
This means that the answer is...
D: Gas
<span>A body wave is a seismic wave that moves through the interior of the earth, as opposed to surface waves that travel near the earth's surface.
P and S waves are body waves. Each type of wave shakes the ground in different ways</span>
15 explanation: look at the graph
Answer: UVA rays occupy the frequency range between 7.1 . 10¹⁴ and 9.4. 10¹⁴ Hz.
Explanation:
UV rays are simply electromagnetic waves, which wavelength is just below the visible spectrum (hance the name ultraviolet, meaning beyond violet).
As any elecromagnetic wave, propagates in the free space at the same speed that light does, i.e. 3.10⁸ m/s.
Also, we know that there exists a direct relationship between the wave speed, her wavelength (distance travelled by the wave during one cycle time) and the frequency (the inverse of the time needed to complete one cycle).
This relationship can be written as the following equation:
v = λ . f ⇒ f = v/λ
Replacing by the extreme wavelengths, we find the corrresponding limit frequencies as follows:
f₁ = 3.10⁸ m/s / 320 . 10⁻⁹ m ⇒ f₁ = 9.4 . 10¹⁴ Hz.
f₂ = 3.10⁸ m/s / 400 . 10⁻⁹ m ⇒ f₂ = 7.1 . 10¹⁴ Hz.
