Question

Part A: How many excess electrons must be distributed uniformly within the volume of an isolated plastic sphere 26.0cm in diameter to produce an electric field of 1500 N/C just outside the surface of the sphere? Part B: What is the electric field at a point 13 cm outside of the surface of the sphere?

Answer 1

Answer:

Q = 28.17 x 10⁻¹⁰ C

E= 375 N/C

Explanation:

Let Q be the charge on plastic sphere.

Field on the surface =k x charge / radius²

Putting the values we get

$1500=\frac{9\times10^9\times Q}{(13\times10^{-2)^2}}$

Q = 28.17 x 10⁻¹⁰ C

No of electrons = Charge / charge on one electron

= $\frac{28.17\times 10^{-10}}{1.6\times10^{-19}}$

= 7 x 10¹⁰

Electric field at 13 cm

= $\frac{9\times10^9\times28.17\times10^{-10}}{26^2\times10^{-4}}$

E= 375 N/C