[填空题]
Compare the electric force hoa31 (rnu2fo 8qcvaj)vlding the elecda f1os2zx/+yh: wi5r tron in orbit $(r\,=\,0.53 \times10^{-10 }\,m)$ around the proton nucleus of the hydrogen atom, with the gravitational force between the same electron and proton. What is the ratio of these two forces? $ \times10^{39 }\,C$
