A solid insulating sphere of radius 0.07 m carries a total charge of 25 pC. Concentric with this sphere is a conducting spherical shell of inner radius 0.12 m and outer radius of 0.18 m, and carrying a total charge of -54 pC. Find (a) the charge distribution for the insulating sphere and the conducting spherical shell, and the magnitude of the electric field at the following distances from the center of the two spheres and shell:(b)0.05 m, (c) 0.10 m, (d) 0.15 m, and (e) 0.25 m.2. For the same cylinder in Sample Problems 1.9 item number 3, find the electric field at a point inside the cylinder.
Answer (1)
Given Data:Solid insulating sphere:Radius = 0.07 mCharge = +25 μCConducting spherical shell:Inner radius = 0.12 mOuter radius = 0.18 mTotal charge = −54 μCRequired:(a) Charge distribution(b) Electric field at distances: 0.05 m, 0.10 m, 0.15 m, and 0.25 mFinal AnswersCharge distribution:+25 μC on the insulating sphere.−25 μC on the inner surface of the shell.−29 μC on the outer surface of the shell.Electric field at different points:r = 0.05 m → Field inside sphere (nonzero, varies with r).r = 0.10 m → Use Coulomb’s law with Q = +25 μC.r = 0.15 m → E = 0 (inside conductor).r = 0.25 m → Use Coulomb’s law with Q = −29 μC.
