Two spherical shells have a common center. the inner shell has radius r1 = 5.00 cm and charge q1 = +4.00×10−6 c; the outer shell has radius r2 = 15.0 cm and charge q2 = −6.00×10−6 c. both charges are spread uniformly over the shell surface. take v = 0 at a large distance from the shells. a) what is the electric potential due to the two shells at the distance r = 2.50 cm from their common center.
b) what is the electric potential due to the two shells at the distance r = 10.0 cm from their common center.
c) what is the electric potential due to the two shells at the distance r = 20.0 cm from their common center.