A proton is 1837 times heavier than a electron. Find the centre of mass of hydrogen atom.
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Answer:
A proton is 1837 times heavier than a electron. Find the centre of mass of hydrogen atom.
Why do protons have a mass exactly 1837 times that of an electron?
“ Why do protons have a mass exactly 1837 times that of an electron?”
The rest mass of a free proton= 1.67239(4)×10^-24 gm.
The rest mass of a free electron=9.1083(3)×10^-28 gm.
Ratio of: (Proton mass/Electron mass)= 1836.12(2)
The number given above are standard accepted values of rest masses of a free proton, and a free electron, and are available in any book of constants.
The number in the paranthesis with the masses or the ratio of the masses is the error in the measured values and the ratio derived from these measured value. It is a compact way of writing the error. The number 4 in paranthesis with the rest mass of say free proton is that error in the rest mass of proton is: 0.00004×10^-24 gm. The number 4 is error in the last decimal place of the value given i.e. it is error in the digit 9 of the resr mass of free proton=1.67239×10^-24 gm. Were the number in the paranthesis be say 15, then the error occurs in the last two digits of the measured value.
We see that the ratio of the mass of a proton to that an electron = 1836. 12. We take this number to be exactly 1836 or for that matter 1837 as a matter of convenience. The ratio does not come out to be exact integer. Even if it were, no great significance will attach to it, it would be merely a coincidence.