Two plastic spheres The figure shows two thin plastic spherical shells (shown in

Question

Two plastic spheres
The figure shows two thin plastic spherical shells (shown in cross section) that are uniformly charged. The center of the larger sphere is at < 0, 0, 0 >; it has a radius of 12 cm and a uniform positive charge of 6 ? 10-9 C. The center of the smaller sphere is at < 25, 0, 0 > cm; it has a radius of 3 cm and a uniform negative charge of -3 ? 10-9 C.

(a) What is the electric field at location A (6 cm to the right of the center of the large sphere)? Neglect the small contribution of the polarized molecules in the plastic, because the shells are very thin and don't contain much matter.
< , ,  > N/C
(b) What is the electric field at location B (15 cm above the center of the small sphere)? Again, neglect the small contribution of the polarized molecules in the plastic, because the shells are very thin and don't contain much matter.
< , , > N/C
(c) What is the force on an electron placed at location B?
< , , > N

i need it like < , , >

i got a) <747, 0 0>

i want b and c

Explanation / Answer

(a) I think your answer is fine.

(b) You don't say what method or equations or approach you used to answer this one. It seems like you understand the principles and formulas involved, so I don't know what you could be missing. Here's how I would solve it:

Assume that the fields from the two spheres are acting as though they are point charges at their centers.

Calculate the two electric fields using the formula you used in (a) and superimpose (add) them.

(0) 4 * ? * ?0 = 4 * 3.14 * 8.85 e-12 = 1.11e-10

(1) El (electric field from large sphere) = Ql / (1.11e-10 * d^2)

= 6e-9 / (1.11e-10 * (0.25^2 + 0.15^2))

= 636.N/C

(2) Es (electric field from small sphere) = Qs / (1.11e-10 * d^2)

= -3e-9 / (1.11e-10 * (0.15^2))

= -1201 N/C

(3) Enet = El + Es

= 636.N/C - 1201 N/C

= -565 N/C

(c) The force on the electron at B is given by:

(4) F = qe * Enet

= (-1.60e-19) * (-565)

= 9.04e-17N

THANKS PLEASE RATE

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