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Three concentric spherical shells of radii R1, R2, R3 (R1 < R2 < R3) carry charges –1, –2 and 4 coulombs, respectively. The charge in coulombs on the inner and outer surfaces respectively, of the outermost shell is—
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- 0 and 4
- 3 and 1
- – 3 and 7
- – 2 and 6
Correct Option: B
As far as the conducting spherical shell of radius R3 is concerned, the charge contained in the volume enclosed by it is – 1 + (– 2) = – 3C. This will induce a charge of + 3C, on the inner surface and a charge of – 3C on the outer surface of this third shell. Also, net charge reside on the outer surface has a charge of + 3C and the outer surface has 4 – 3 = 1C. 
