Answer : The energy released by an electron in a mercury atom to produce a photon of this light must be, 
Explanation : Given,
Wavelength = 
conversion used : 
Formula used :

As, 
So, 
where,
= frequency
h = Planck's constant = 
= wavelength = 
c = speed of light = 
Now put all the given values in the above formula, we get:


Therefore, the energy released by an electron in a mercury atom to produce a photon of this light must be, 
Potassium outermost electron occupy "4s" orbital
Answer:
You could observe the cell wall in all kingdoms except for the animals. That would be cells of plants, protists (algae), fungi, bacteria and achaea.