The answer is A. the principal energy level
<h2>Why?</h2>The principal energy level or principal quantum number n, tell us about the position of an determined electron in the energy levels relative to the greater average distance of an electron from the nucleus, the larger the value of n and the higher its energy.
The principal energy levels contains n sublevels, orbitals and
electrons.
For example, the number 1, has one orbital which is contained in a energy sublevel, its called s orbital, and it's just an orbital with 2 electrons.
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Answer:
Explanation:
Mass of block=10 kg
Applied horizontal force =F=20 N
Friction force=f=10 N
We have to find the acceleration of block.
Net force=Applied horizontal force-friction force
Where F= Horizontal force
f=Friction force
m=Mass of object
a=Acceleration of object
Hence, the acceleration of the block=