Answer:
The energy in its ground state is 10 meV.
Explanation:
It is given that,
The energy of the electron in its first excited state is 40 meV.
Energy of the electron in any state is given by :

For ground state, n = 1
.............(1)
For first excited state, n = 2
.............(2)
Dividing equation (1) and (2), we get :


So, the energy in its ground state is 10 meV. Hence, this is the required solution.
E = mc^2
m = e/c^2
m = 2.7*10^16/(300000^2)
m = 300000
The answer is B I hope this helps luv
Answer:
1
The mass of the Potassium-40 is 
2
The Dose per year in Sieverts is 
Explanation:
From the question we are told that
The isotopes of potassium in the body are Potassium-39, Potassium-40, and Potassium-
41
Their abundance is 93.26%, 0.012% and 6.728%
The mass of potassium contained in human body is
per kg of the body
The mass of the first body is 
Now the mass of potassium in this body is mathematically evaluated as

substituting value


The amount of Potassium-40 present is mathematically evaluated as
0.012% * 0.024


The dose of energy absorbed per year is mathematically represented as

Where E is the energy absorbed which is given as 
Substituting value


The Dose in Sieverts is evaluated as


