The membrane of the axon of a nerve cell is a thin cylindrical shell of radius r = 10-5 m, length L = 0.32 m, and thickness d = 10-8 m. The membrane has a positive charge on one side and a negative charge on the other. Thus, it acts like a parallel-plate capacitor of area A = 2pirL and separation d. Its dielectric constant is kappa = 4. If the potential difference across the membrane is 74 mV, determine the magnitude of the charge on each side of the membrane.

Respuesta :

Answer:

5.3 x 10⁻⁹ C

Explanation:

r = radius of cylindrical shell = 10⁻⁵ m

L = length = 0.32 m

A = area

Area is given as

A = 2πrL

A = 2 (3.14) (10⁻⁵) (0.32)

A = 20.096 x 10⁻⁶ m²

d = separation = 10⁻⁸ m

[tex] k_{appa} [/tex] = dielectric constant = 4

Capacitance is given as

[tex]Q=\frac{k_{appa}\epsilon _{o}A}{d}[/tex]                               eq-1

V = Potential difference across the membrane = 74 mV = 0.074 Volts

Q = magnitude of charge on each side

Magnitude of charge on each side is given as

Q = CV

using eq-1

[tex]Q=\frac{k_{appa} \epsilon _{o}AV}{d}[/tex]

Inserting the values

[tex]Q=\frac{4 (8.85\times 10^{-12})(20.096\times 10^{-6})(0.074)}{10^{-8}}[/tex]

Q = 5.3 x 10⁻⁹ C

The membrane is parallel and act as a parallel plate capicitor.The magnitude of the charge on each side of the membrane will be 5.3×10⁻⁹C.

What is parallel plate capacitor ?

It is an type capacitor is an in which two metal plates arranged in such away so that they are connected in parallel andhaving some distance between them.

A dielectric medium is must in between these plates help to stop the flow of electric current through it due to its non-conductive nature .

The given data in the problem is;

r is the radius of cell of thin cyliner=10⁻⁵m

L is the length =0.32

d is the thickness =10⁻⁸m

K is the dielectric constant=4

v is the potential difference across the membrane=74 mv=0.074 v

q is the megnitude of charge=?

A is the area of capicitor=2πrl

[tex]\rm A = 2\pi rl\\\\\rm A= 2\times3.14\times10^{-5}\times0.32\\\\\rm A= 20.096\times10^{-6}[/tex]

The given formula for the parallel plate capicitor as ,

[tex]\rm Q=\frac{K\varepsilon _0AEr}{d} \\\\\rm Q=\frac{4\times(8.85\times10^{-12})(20.096\times10^{-6}\times0.074}{10^{-8}}\\\\\rm Q=5.3\TIMES10^{-9}\;C[/tex]

Hence the charge on each side of the membrane will be 5.3×10⁻⁹C.

To learn more about the parallel plate capicitor refer to the link;

https://brainly.com/question/12883102

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