- Electricity and Magnetism
3.1. Due to polarization of the insulator rod AB,
the point charge +q1 will be acted upon, in addi-
tion to the point charge —q 2 , by the polarization
charges formed at the ends of the rod (Fig. 206).A
®
ql g2
Fig. 206The attractive force exerted by the negative charge
induced at the end A will be stronger than the re-
pulsive force exerted by the positive charge in-
duced at the end B. Thus, the total force acting
on the charge ty 1 will increase.
3.2. In the immediate proximity of each of point
charges, the contribution from the other charge
to the total field strength is negligibly small, and
hence the electric field lines emerge from (enter)
the charge in a spatially homogeneous bundle,
their total number being proportional to the mag-
nitude of the charge. Only a fraction of these lines
gets into a cone with an angle 2a at the vertex
near the charge +qv The ratio of the number of
these lines to the total number of the lines emerging
from the charge -Fq 1 is equal to the ratio of the
areas of the corresponding spherical segments:
2aRR (1— cos a) 1
(1—cos a).
4n/i 2 2Since the electric field lines connect the two charges
of equal magnitude, the number of lines emerging