question_answer

Find the number of protons whose mass is equal to I S.I unit of mass.

Answer:

The S.I unit of mass is kilogram. Let the number of protons be\[x\]. \[\Rightarrow \]\[1\text{ }Kg=x\times mass\text{ }of\text{ }one\text{ }proton\] \[\Rightarrow \]\[1\text{ }Kg=x\times 1.6\times {{10}^{27}}kg\] (Q mass of a proton\[=1.6\times {{10}^{27}}kg\]) \[\Rightarrow \]\[x=\frac{1}{1.6\times {{10}^{-27}}}=\frac{{{10}^{27}}}{1.6}\] \[=\frac{10}{1.6}\times {{10}^{26}}=6.3\times {{10}^{26}}\]protons Therefore, the mass of\[6.3\times {{10}^{26}}\]protons is equal to 1 S.I unit of mass (kg).