Capacitance of a Wire
A wire of radius 2.30 cm produces
an electric field of 6.37 x 104 N/C and a potential of 50 volts
at a distance of 8.63 cm from the wire (perpendicular to the wire). Find
the capacitance per unit length and the surface charge density.
Solution:
We take a Gaussian surface which
is a cylinder surrounding the wire at 8.63 cm. Using AW for
the surface area of the wire and AG for the surface area of
the Gaussian surface,
Capacitance is defined as Q/V:
