A small conducting spherical shell with inner radius a and outer radius b is con
ID: 1872889 • Letter: A
Question
A small conducting spherical shell with inner radius a and outer radius b is concentric with a larger conducting spherical shell with inner radius c and outer radius d. The inner shell has a total charge -1q and the outer shell has a total charge +4q.
Which of the following statements are true: (Give ALL correct answers, i.e., B, AC, BCD...)
A) The total charge on the inner surface of the small shell is -1q.
B) The total charge on the inner surface of the large shell is zero.
C) The radial component of the electric field in the region c less than r less than d is given by +4q/(4 pi epsilon0 r2).
D) The electric field in the region r less than a is zero.
E) The total charge on the outer surface of the small shell is -5q.
F) The radial component of the electric field in the region r greater than d is given by +3q/(4 pi epsilon0 r2).
G) The total charge on the outer surface of the large shell is +3q.
Explanation / Answer
(A) for a <r < b , E = 0
Qin = Qa = 0
false
(B) as explained above , True
(C) c < r < d : field inside conuctor is zero.
E = 0
false
(D) for r< a ; E = 0 True
(E) Qa + Qb = - q
so Qb = - q
false
(F) for r > d ; Qin = - q + 4 q = 3 q
E ( 4pi r^2) =Qin /e0 = 3 q / e 0
E = (3 q) /(4 pi e0 r^2)
True
(G) Qc + Qa + Qb = 0
Qc = + q
Qc + Qd = 4 q
Qd = 4q - q = 3 q
True
Ans: BDF G