A conducting sphere of radius 100 cm is charged to a potenti

A conducting sphere of radius 100 cm is charged to a potential of 30-Stat volts. (Work CGS units.) What charge is on the sphere? What is the energy stored in the field? If this sphere is connected to a second identical uncharged sphere by a long wire, what is the final energy in the system? Consider the second sphere to be at so large a distance away that you can neglect any interference between the two spheres.

Solution

a)

Electric potential due to a point charge is given by

V=KQ/r

=>Q = Vr/Q =30*1/(9*10⁹)

Q=3.33*10^-9 C

b)

Energy stored in the field is

U=(1/2)CV²

Since Q=CV

U=(1/2)QV =(1/2)*(3.333*10^-9)*30

U=5*10^-8 J

c)

Both the spheres have same charge ,since charge from charged sphere will be transferred to uncharged sphere ,so

Q=3.33*10^-9 C