91Ó°ÊÓ

Consider a short cylinder, of radius $a$and length $L$, carries a "frozen-in" uniform polarization $P$, parallel to its axis .

Draw the circuit diagram of electric field for$\text{L}≫\text{a}$ .

Figure 1

For$\text{L}≫\text{a}$ .

In the event that $\text{L}≫\text{a}$, the field will roughly resemble that of a physical dipole, with "point charges" of magnitude$Â\pm \mathrm{PA}$ spaced apart.

Draw the circuit diagram of electric field for $\text{L}≪\text{a}$.

Figure 2

The field between the top and bottom of the cylinder in the case $\text{L}≪\text{a}$will roughly resemble that of a parallel-plate capacitor with surface charge densities$Â\pm P$ on the top and bottom.

Draw the circuit diagram of electric field for $\text{L}≈\text{a}$

Figure 3

Simply take a look at the preceding two situations; they both have surface charge densities$Â\pm P$ on the top/bottom. About as the photo depicts, the field looks.

The surface bound charge is the only bound charge present in all three scenarios since the polarisation is constant, ${\mathrm{ÒÏ}}_b=0$.