I think it is C) the resting position of the wave.
In atoms, electrons surround the nucleus in specific energy levels.
Answer: Option B
<u>Explanation:
</u>
Atom, actually considered as the tiny part that is ever present in this universe. Many theories and experiments were conducted, for studying what was present inside of an atom, and many theories came into light.
And finally, Bohr-Sommerfeld Theory stated the final conclusion, that the positive charge is at the centre of the nucleus, and all the electrons revolve in their specific energy levels. If an atom wants to move to lower energy state, it should emit energy, whereas for going to higher state, it should gain energy.
A.
The planet contains matter and energy so it is a system.
<span><span>Big Bang- January 1
</span><span>Origin of Milky Way Galaxy- May 1
</span><span>Origin of the solar system- September 9
</span><span>Formation of the Earth- September 14
</span><span>Origin of life on Earth<span>- September 25</span></span></span>
An example of a system with decreasing gravitational potential energy is a ball in free fall.
At its initial height h, the ball has a gravitational potential energy equal to

where m is the ball mass and g is the gravitational acceleration. As the ball falls toward the ground, its height h decreases, and so its gravitational potential energy decreases as well, according to the formula

where h' is the new height of the ball.