Flux and nonconducting shells . A charged particle is suspended at the center of
ID: 2271933 • Letter: F
Question
Flux and nonconducting shells. A charged particle is suspended at the center of two concentric spherical shells that are very thin and made of nonconducting material. Figure (a) shows a cross section. Figure (b) gives the net flux through a Gaussian sphere centered on the particle, as a function of the radius r of the sphere. The scale of the vertical axis is set by s = 28.0 Ý 105 N·m2/C. (a) What is the charge of the central particle? Give your answers in µC. What are the net charges of (b) shell A and (c) shell B?
Explanation / Answer
(a) Inside A, the flux = q/?0 = ?s *2/5 = 1.12*10^6, so q = 9.91*10^(-6) C = 9.91 ?C
(b) between A and B, the flux = (q + qA)/?0 = ?s *(-4/5) = -2.24*10^6, so q + qA = -1.98*10^(-5) C = -19.8 ?C
so qA = -29.7 ?C
(c) outside B, the flux = (q + qA + qB)/?0 = ?s *6/5 = 3.14*10^6, so q + qA+ qB = 2,78*10^(-5) C = 27.8 ?C
so qB = 27.8 - 9.9 - (-19.8) = 37.7 ?C