What it looks to be that you found in A was the "initial"...b/c the question asks:
<span>"how much energy does the electron have 'initially' in the n=4 excited state?" </span>
<span>"final" would be where it 'finally' ends up at, ie. its last stop...as for this question...the 'ground state' as in its lowest energy level. </span>
The answer comes to: <span>−1.36×10^−19 J</span>
You use the same equation for the second part as for part a.
<span>just have to subract the 2 as in the only diff for part 2 is that you use 1squared rather than 4squared & subract "final -initial" & you should get -2.05*10^-18 as your answer. </span>
<span>Objects that fall near Earth’s surface are rarely in free fall.
"Free fall" is the situation where the ONLY force on an object is
the force of gravity, and nothing else.
Objects near Earth's surface are almost always surrounded by air.
If they are falling, then the air is exerting forces on them, and they
are not in "free fall".</span>
According to Archimedes' Principle, an Object's density determines the depth it will get by displacing the liquid or gas molecules... More the density, more it's depth.
