A metal sphere of radius 15 cm has a net charge of 3.0 $ 10#8 C. (a) What is the electric field at the sphere’s surface? (b) If V ! 0 at infinity, what is the electric potential at the sphere’s surface? (c) At what distance from the sphere’s surface has the electric potential decreased by 500 V?

Respuesta :

Answer:

E = 1.20 × [tex]10^{4}[/tex] N/C

V = 1800 V

x = 0.058 m

Explanation:

given data

radius = 15 cm

net charge = 3 × [tex]10^{-8}[/tex] C

electric potential decreased = 500 V

solution

we get here electric field at the sphere’s surface that is

electric field at the sphere’s surface E  =  [tex]\frac{q}{4\pi \epsilon _o R^2}[/tex]   ............1

put here value

electric field at the sphere’s surface E  = [tex]\frac{3\times 10^{-8}\times 8.99\times 10^9}{ 0.15^2}[/tex]    

E = 1.20 × [tex]10^{4}[/tex] N/C

and

potential on surface of sphere is

V =  [tex]\frac{q}{4\pi \epsilon _o R}[/tex] ................2

V = [tex]\frac{3\times 10^{-8}\times 8.99\times 10^9}{ 0.15}[/tex]  

V = 1800 V

and

now we get distance that is x

and we know here

ΔV = V(x) - V   ..............3

substitute here value

-500V = [tex]\frac{q}{4\pi \epsilon _o } \times (\frac{1}{R+x} - \frac{1}{R})[/tex]

-500 V = [tex]{3\times 10^{-8}\times 8.99\times 10^9} \times (\frac{1}{0.15+x} - \frac{1}{0.15})[/tex]

solve it we get x

x = 0.058 m