(b) Estimate the
accelerations of electron and proton due to the electrical force of their
mutual attraction when they are 1 Å (= 10-10 m) apart (mp = 1 67 ×
10–27 kg, me = 9 11 × 10–31 kg)
Solution
(a) (i) The electric force between an electron and a proton at a distance
r apart is:
2
2
0
41
e
e
F
r
ε
= −
π
where the negative sign indicates that the force is attractive