Medium· Electrostatic Potential (Work Done to Move a Charge in Electrostatic Field)· +4 / −1
A unit positive point charge is taken slowly through an infinitesimally thin tube that is inside a charged dielectric sphere of radius , having uniform positive charge density , as shown in the figure. The initial and final positions of the charge are marked by and at distance and respectively, from the centre of the sphere. In this process, the magnitude of the total work done on the point charge is . The value of is :
( is the permittivity of vacuum)
Figure: a sphere of radius with centre and uniform charge density . is at distance and at distance from , on different sides. A thin tube runs from to through the sphere, along which the charge is moved.
