Two parallel-plate capacitors have the same plate area. Capacitor 1 has a plate separation twice that of capacitor 2, and the quantity of charge you place on capacitor 1 is four times the quantity you place on capacitor 2. Part A How do the potential differences across each of the two capacitors compare to each other?

Respuesta :

Answer:

[tex]V_1=8 V_2[/tex]

Explanation:

Given that:

  • Area of the plate of capacitor 1= Area of the plate of capacitor 2=A
  • separation distance of capacitor 2, [tex]d_2=d[/tex]
  • separation distance of capacitor 1, [tex]d_1=2d[/tex]
  • quantity of charge on capacitor 2, [tex]Q_2=Q[/tex]
  • quantity of charge on capacitor 1, [tex]Q_1=4Q[/tex]

We know that the Capacitance of a parallel plate capacitor is directly proportional to the area and inversely proportional to the distance of separation.

Mathematically given as:

[tex]C=\frac{k.\epsilon_0.A}{d}[/tex].....................................(1)

where:

k = relative permittivity of the dielectric material between the plates= 1 for air

[tex]\epsilon_0 = 8.85\times 10^{-12}\,F.m^{-1}[/tex]

From eq. (1)

For capacitor 2:

[tex]C_2=\frac{k.\epsilon_0.A}{d}[/tex]

For capacitor 1:

[tex]C_1=\frac{k.\epsilon_0.A}{2d}[/tex]

[tex]C_1=\frac{1}{2} [ \frac{k.\epsilon_0.A}{d}][/tex]

We know, potential differences across a capacitor is given by:

[tex]V=\frac{Q}{C}[/tex]..........................................(2)

where, Q = charge on the capacitor plates.

for capacitor 2:

[tex]V_2=\frac{Q}{\frac{k.\epsilon_0.A}{d}}[/tex]

[tex]V_2=\frac{Q.d}{k.\epsilon_0.A}[/tex]

& for capacitor 1:

[tex]V_1=\frac{4Q}{\frac{k.\epsilon_0.A}{2d}}[/tex]

[tex]V_1=\frac{4Q\times 2d}{k.\epsilon_0.A}[/tex]

[tex]V_1=8\times [\frac{Q.d}{k.\epsilon_0.A}][/tex]

[tex]V_1=8 V_2[/tex]