Two positive point charges of 12 μC and 8 μCare 10 cm apart. The work done in bringing them 6 cm closer is
5.8 J
5.8 eV
13 J
13 eV
W=Uf-Ui=9×109×Q1Q21r2-1r1 ⇒W=9×109×12×10-6×8×10-614×10-2-110×10-2 =12.96 J≈13 J