Atomic physicists ignore the effect of gravity within an atom. To see why, calculate and compare the gravitational and electrical forces between an electron and a proton separated by 10?10 m. The charges and masses are given on the inside back cover.

Solution 5P Step 1: Here we need to calculate the force of gravity electrical force between electron and proton Considering the data required 31 Mass of electron m = e.1 × 10 kg Mass of proton m = 1p6 × 10 27 kg 11 3 2 1 Gravitational force constant G = 6.67 × 10 m s kg 10 Distance between the particles r = 1 × 10 m Charge of electron q = 1.6 × 10 19 9 Coulomb constant K = 8.9 × 10 F/m Step 2 : Let us calculate the gravitational force between the charges, it is obtained using m ×m F g G e2 p r Substituting the values we get 9.1 ×101kg ×1.6×102kg F g 6.67 × 10 11m s kg ( 1 10 2 ) (1×10 m) F g 6.67 × 10 11m s kg (1.456 × 10 37kg ) 48 F g 9.711 × 10 N