A cylindrical capacitor has two co-axial cylinders of length 15 cm and radii 1.5 cm and 1.4 cm. The outer cylinder is earthed and the inner cylinder is given a charge or 3.5 `muC.` Determine the capacitance of the system and the potential of the inner cylinder. Neglect end effects (i.e., bending of field lines at the ends).

Explanation

`l=15 cm =15 xx 10^(-2)m " "a=1.4cm =1.4 xx 10^(-2)m" b=1.5cm =1.5 "xx 10^(-2)m Q=3.5muC`
`C=(2pi epsi_(0) l)/(2.303 log(b/a))=(1 xx 15 xx 10^(-2))/(2 xx 3.303 log ((1.5)/(1.4)) xx 9 xx 10^(9))=1.2 xx 10^(-10)F`
`V=Q/(2pi epsi_(0)l) log (b/a) =(2 xx 9 xx 10^(9) xx 3.5 xx 10^(-6))/(15 xx 10^(-2)) log""((1.5)/(1.4))=2.9 xx 10^(4)V`