Answer:
As you may know, each element has a "fixed" number of protons and electrons.
These electrons live in elliptical orbits around the nucleus, called valence levels or energy levels.
We know that as further away are the orbits from the nucleus, the more energy has the electrons in it. (And those energies are fixed)
Now, when an electron jumps from a level to another, there is also a jump in energy, and that jump depends only on the levels, then the jump in energy is fixed.
Particularly, when an electron jumps from a more energetic level to a less energetic one, that change in energy must be compensated in some way, and that way is by radiating a photon whose energy is exactly the same as the energy of the jump.
And the energy of a photon is related to the wavelength of the photon, then we can conclude that for a given element, the possible jumps of energy levels are known, meaning that the possible "jumps in energy" are known, which means that the wavelengths of the radiated photons also are known. Then by looking at the colors of the bands (whose depend on the wavelength of the radiated photons) we can know almost exactly what elements are radiating them.
Answer:
31.831 Hz.
Explanation:
<u>Given:</u>
The vertical displacement of a wave is given in generalized form as
<em>where</em>,
- A = amplitude of the displacement of the wave.
- k = wave number of the wave =
= wavelength of the wave.- x = horizontal displacement of the wave.
= angular frequency of the wave = 
.- f = frequency of the wave.
- t = time at which the displacement is calculated.
On comparing the generalized equation with the given equation of the displacement of the wave, we get,
therefore,
It is the required frequency of the wave.
Answer:
d. It increases numerical aperture and maintains a uniform light speed.
Explanation:
In optical microscopes, various immersion mediums are used to improve or enhance the resolution. Immersion oils like cedar and Leica oils are one of those mediums which are used to improve resolution by increasing the numerical aperture and keeping the speed of light uniform.
<h2><em>C. translational motion</em></h2><h2><em>HOPE IT HELPS !!!!!</em></h2>
Answer:
D. 130 J
Explanation:
The coefficient of performance for a machine that is being used to cool, is given by:
Here 
is the heat removed from the cold reservoir, W is the work required, that is, the energy required to remove the heat from the interior of the house, 
is the cold temperature and 
is the hot temperature. Recall use absolutes temperatures(
). Replacing and solving for W:
