Question

What force does the electric field of a charged infinite plane act with on each metre of a charged infinitely long filament placed in this field? The charge linear density on the filament is 3x10^- 8 C/cm and its surface density on the plane is 2x10^-8 C/cm2.

Answer 1

$E=\frac{\sigma}{2\varepsilon_0},$

$E=\frac Fq,~q=\tau l,$

$\frac F{\tau l}=\frac{\sigma}{2\varepsilon_0},$

$F_1=\frac Fl=\frac{\sigma\tau}{2\varepsilon_0}=33.9~\frac Nm.$