The membrane of a living cell can be approximated by a parallel-plate capacitor with plates of area 5.41 10-9 m2, a plate separation of 8.5 10-9 m, and a dielectric with a dielectric constant of 4.5.

What is the energy stored in such a cell membrane if the potential difference across it is 0.0679 V?

? J

Respuesta :

Answer:

Energy stored in cell membrane is 5.83 x 10⁻¹⁴ J.

Explanation:

Given :

Area of parallel plate capacitor,A = 5.41 x 10⁻⁹ m²

Distance between the plates,d = 8.5 x 10⁻⁹ m

Dielectric constant, k = 4.5

Capacitance of a parallel plate capacitor is given by the relation :

C = (kε₀A)/d

Here ε₀ is vacuum permittivity and its value is 8.85 x 10⁻¹² F/m.

Substitute the suitable values in the above equation.

[tex]C = \frac{4.5\times8.85\times10^{-12}\times5.41\times10^{-19} }{8.5\times10^{-19}}[/tex]

C = 2.53 x 10⁻¹¹ F

Potential difference between the plate, V = 0.0679 V

Energy stored in a capacitor is given by the relation :

[tex]E = \frac{1}{2}CV^{2}[/tex]

Substitute the values of C and V in the above equation.

[tex]E = \frac{1}{2}\times2.53\times10^{-11}\times (0.0679)^{2}[/tex]

E = 5.83 x 10⁻¹⁴ J