A nonconducting sphere has radius R = 1.29 cm and uniformly distributed charge q = +3.83 fC. Take the electric potential at the sphere's center to be V0 = 0. What is V at radial distance from the center (a) r = 0.560 cm and (b) r = R? (Hint: See an expression for the electric field.)

Respuesta :

Answer:

a) -2.516 × 10⁻⁴ V

b) -1.33 × 10⁻³ V

Explanation:

The electric field inside the sphere can be expressed as:

[tex]E= \frac{kqr}{R^3}[/tex]

The potential at a distance can be represented as:

V(r) - V(0) = [tex]-\int\limits^r_0 {\frac{kqr}{R^3} } \, dr^2[/tex]

V(r) - V(0) = [tex][\frac{qr^2}{8 \pi E_0R^3 }][/tex]₀

V(r) =   [tex]-[\frac{qr^2}{8 \pi E_0R^3 }][/tex]₀

Given that:

q = +3.83 fc = 3.83 × 10⁻¹⁵ C

r = 0.56 cm

 = 0.56 × 10⁻² m

R = 1.29 cm

  =  1.29 × 10⁻² m

E₀ = 8.85 × 10⁻¹² F/m

Substituting our values; we have:

[tex]V(r)[/tex] [tex]= -\frac{(3.83*10^{-15}C)(0.560*10^{-2}m)^2}{8 \pi (8.85*10^{-12}F/m)(1.29*10^{-2}m)^3}[/tex]

[tex]V(r)[/tex] = -2.15  × 10⁻⁴ V

The difference between the radial distance  and center can be expressed as:

V(r) - V(0) = [tex]-\int\limits^R_0 {\frac{kqr}{R^3} } \, dr^2[/tex]

V(r) - V(0) =  [tex][\frac{qr^2}{8 \pi E_0R^3 }]^R[/tex]

V(r) = [tex]-\frac{qR^2}{8 \pi E_0R^3 }[/tex]

V(r) = [tex]-\frac{q}{8 \pi E_0R }[/tex]

V(r) [tex]= -\frac{(3.83*10^{-15}C)}{8 \pi (8.85*10^{-12}F/m)(1.29*10^{-2}m)}[/tex]

V(r) = -0.00133

V(r) = - 1.33 × 10⁻³ V