A spherical cell has a radius of 2.3 μm , and the phospholipid bilayer that constitutes its membrane has a thickness of 3.75 nm . At its normal resting state, the outer membrane is at a voltage of 0V, and the inner membrane is at a voltage of -70mV. The dielectric constant of the cell membrane is roughly 9.0. What is the capacitance of the cell? (Note: the surface area of a sphere is 4πr2)

Answers

Answer 1

Answer:

Explanation:

The cell is acting like a shell .

Capacity of a shell is given by the following expression.

C= 4πk ε₀ x ab / (b-a )

k is dielectric constant , b and a are outer and inner radius ε₀ is a constant .

Here a = 2.3 x 10⁻⁶ m

b = 2.3 x 10⁻⁶ + .00375 x 10⁻⁶

= 2.30375 x 10⁻⁶ m

b -a = 3.75 x 10⁻⁹ m .

k = 9

4π ε₀ = 1 / 9 x 10⁹ = .111 x 10⁻⁹

C=  .111 x 10⁻⁹ x 9 x 2.3 x 10⁻⁶ x 2.30375 x 10⁻⁶ / 3.75 x 10⁻⁹

= 1.41 x 10⁻¹² F

= 1.41 pF .


Related Questions

A car at a position 150 km [W] of Toronto travels to a position 400 km [W] of
Toronto. The total displacement of the car is:

Answers

Answer:

The total displacement of the car is 250 km.

Explanation:

Given that,

A car at a position 150 km [W] of Toronto travels to a position 400 km [W] of  Toronto.

Total displacement = final position - initial position

= 400 km - 150 km

= 250 km

So, the total displacement of the car is 250 km.

What is the direction of the magnetic field due to the positive charge at the location of the negative charge

Answers

Answer:

A positively charged object moving due west in a region where the Earth's magnetic field is due north experiences a force that is straight down as shown.

A negative charge moving in the same direction would feel a force straight up.

If the resistance is 25 and the voltage is 75. What is the amount of current that I will be getting?

Answers

Answer:h

Explanation:

the unit of energy is same as that of work i.e joule give reason​

Answers

"Energy" is the ability to do work.

"Work" is the process of using energy.

How much current flows in the circuit if two resistors of 6 connected in parallel are
supplied with potential difference of 12 volts?​

Answers

Answer:

4 A

Explanation:

Firstly we need to calculate the equivalent resistance. Since, two resistors of 6 connected in parallel, so equivalent resistance will be given by,

[tex]\longrightarrow[/tex] 1/R = 1/R1 + 1/R2

[tex]\longrightarrow[/tex] 1/R = (1/6 + 1/6) Ω

[tex]\longrightarrow[/tex] 1/R = (1 + 1)/6 Ω

[tex]\longrightarrow[/tex] 1/R = 2/6 Ω

[tex]\longrightarrow[/tex] R = 6/2 Ω

[tex]\longrightarrow[/tex] R = 3 Ω

We know that,

[tex]\longrightarrow[/tex] V = IR

V denotes p.d (12V)I denotes currentR denotes resistance (3 Ω)

[tex]\longrightarrow[/tex] 12 = I × 3

[tex]\longrightarrow[/tex] 12 ÷ 3 = I

[tex]\longrightarrow[/tex] 4 Ampere = I

Why does time have a direction? Please give your ideas I want to see them. Brainliest f0r most effort.:)

Answers

Answer:

it's a rule like water !!!!

Explanation:

Most importantly, time appears to run forward always never backwards. in other words there's perceived arrow of time and there's thermodynamic arrow of time, and they always point in a forward direction

for every system there are more states that seem chaotic then states that seem ordered.

the arrow of time seems to have something to do with that tendency. but to get from one instance to another where things get more entropy, we already need some kind of time, gotta admit that.

some (physicists) believe that time is an illusion, that the whole universe is already set in stone, like a block (the idea is therefore called block universe). from the perspective of a godlike outside observer the universe would be like a book, or a 4D movie. the characters might feel a movement of things in a direction, but rewinding it wouldn't feel different in any instance because the order in wich things happen is already written.

a different idea is that there are infinite many different futures and the further they are away, the less we can know for sure about them in a physical way. and this might also be work for the past, so that different parts could lead to one present.

when macroscopic information is deleted, it might not be reversible, so the past gets ultimately blurry. one example for deletion of macroscopic information this is the Library of Alexandria wich burned down.

all the quantum information is still conserved, but the order of things (like letters on pages) is lost and could have been in different configurations before. we can't ultimately not even see the past, as much as we would try.

personally the idea that the past is written in stone but the future is in flux doesn't make any sense for me. because than I could have free will now, but not from the perspective 10 days later.

the present would be a very special thing than, the stage where the universe likes to play.

maybe we can get a grasp on time if we look at it like rules for a game, like a cardboard game.

To get from one configuration to the next ,we must follow rules. like throwing dice and moving in monopoly.

gravity would be a simple real world example for such a rule, a natural law.

But no one would have a firm clue where this rules came from.

TLDR: I don't know and neither does anyone else for sure, not even top notch scientists.

the hardest questions are easy to formulate, but maybe even impossible for us to answer in a satisfying way. I hope we will understand those hard questions better one day, and maybe even get answers.

TRUE OR FALSE. if an object covers equal distance at equal intervals of time, then it is moving at constant speed and not accelerating

Answers

Answer:

True

Explanation:

Speed = distance/time

If distance and time are the same, then the right hand side of the equation remains the same, causing us to solve the left to the same value

As the distance is the same (say 50m) and the time is the same (say 50s) then the speed must be the same (1m/s)

What happens to the electric force between two particles if the distance
between them is doubled?
A. It decreases to half the original force.
B. It increases to twice the original force.
C. It increases to 4 times the original force.
D. It decreases to 1/4 of the original force.

Answers

Answer:

D.

Explanation:

Force and distance are inversely related, so a greater distance results in a weaker force.

Naomi Osaka, a Japanese-African-American tennis player is the 2021 Australian Open Champion, and the first Asian tennis player in Women's Tennis Association (WTA) history to be ranked first in Singles. To celebrate her win, Naomi Osaka hits a ball into the stands at 40. m/s and at an angle 30.° above the horizontal. On its way down, the ball is caught by a spectator 12 m above the point where the ball was hit.

a) Calculate the time it takes the tennis ball to reach the spectator.

b) Calculate the ball's horizontal range (horizontal distance travelled).

Answers

Answer:

(a) t = 0.75 s

(b) d = 26 m

Explanation:

Height, h = 12 m

Angle, A = 30 degree

initial velocity, u = 40 m/s

(a) Let the time is t.

Use second equation of motion

 [tex]h = u t + 0.5 at^2\\\\12 = 40 sin 30 t - 0.5 \times10 \times t^2\\\\12 = 20 t - 5 t^2\\\\5 t^2 - 20 t + 12 =0 \\\\t = \frac{20\pm \sqrt{400-240}}{10}\\\\t = \frac{20\pm 12.65}{10}\\\\t = 3.3 s, 0.75 s[/tex]

(b) d = u cos A t

d = 40 x cos 30 x 0.75 = 26 m

What is the enthalpy change, AH, for this reaction? Show your work to receive full credit. URGENT PICTURE INCLUDED !!!

Answers

Answer:

150 kJ

Explanation:

Applying,

ΔH = Energy level of Product(E') - Energy level of reactant(E)

Where ΔH = enthalpy change, E' and E = energy level of the product and the reactant respectively

ΔH = E'-E............. Equation 1

From the diagram,

Given: E' = 200 kJ, E = 50 kJ

Substitute these values into equation 1

ΔH = 200-50

ΔH = 150 kJ

Hence the enthalpy change for the reaction is 150 kJ

How do the rocks in the mantle move?
A. They do not move.
B. They move in convection currents.
C. They flow like water.
D. They move on top of the crust.

Answers

Answer:

b. they move in convection currents.

Explanation:

i learned this in 4th grade

What do you think Jose’s grandmother meant by saying that the bread was too dense? What other things can you think of that are “dense”?

Answers

The bread was most likely heavy

Answer:

What I think that Jose's grandmother meant by saying that the bread was too dense is that she thinks the bread is too heavy or it can even mean to be too compacted in substance. The matter in the bread are close together and not spread out like in the air, when the matter in the air starts to come closer together it starts to make fog, because it is becoming more dense. Some more things that are heavy or dense are things like a big stereo speaker, an anvil, or even a big piece of wood used to build.

Explanation:

Select the correct answer. The motion of a car on a position-time graph is represented with a horizontal line. What does this indicate about the car’s motion? A. It’s not moving. B. It’s moving at a constant speed. C. It’s moving at a constant velocity. D. It’s speeding up.

Answers

If the car's motion appears as a horizontal line on a position-time graph, it shows that as time changes, the car's position doesn't change.

This is just a complicated way to say that the car is not moving. (A)

Answer: It's not moving.

Explanation:

I got it correct on edmentum.

What is displacement?
An objects overall change in position
The total measure of how far one travels
a change in direction

Answers

Answer:

An object overall change in position

Explanation:

ans maybe corre6

at which point is the Kinetic energy the lowest?​

Answers

Answer:

the lowest kinetic energy point is option D

A piano string of density 0.0050 kg/m is under a tension of 1,350 N. Find the velocity with which a wave travels on the string.

Answers

Answer:

519.62 m/s

Explanation:

Applying,

v = √(T/m').............. Equation 1

Where v = velocity of the wave, T = Tension on the string, m' = mass per unit length of the string

From the question,

Given: T = 1350 N, m' = 0.005 kg/m

Substitute these values into equation 1

v = √(1350/0.005)

v = √(270000)

v = 519.62 m/s

In the diagram, q1 = +2.00 x 10-5 C,
q2 = +3.80 x 10-6 C, and q3 = +5.30 x 10-5 C.
What is the electric potential energy, Ue, for
charge qy? Include the correct sign (+ or -).

Answers

Answer:

     U = 3.59 10⁻⁹ J

Explanation:

Electric potential energy is

             U = k ∑ [tex]\frac{q_iq_j }{r_i_j}[/tex]

in this case

            U = k (q₁q₂ / r₁₂ + q₁q₃ / r₁₃ + q₂q₃ / r₂₃)

the distances are

            r₁₂ = 1.15

            r₁₃ = 1.15 +2.88 = 4.03 m

            r₂₃23 = 2.88

we substitute

            U = 9 109 (2 10-5 3.8 10-6 / 1.15 + 2 10-5 5.30 10-5 / 4.03 + 3.8010-6 53 010-5 / 2.88)

             U = 9 109 (6.609 10-11 + 2.63 10-10 + 6.99 10-11)

            U = 9 109 (39,899 10-11)

            U = 3.59 10⁻⁹ J

Answer:

Q2 = 0.0346 J

Explanation:

I don't know what Q1 is but I did solve for Q2. I'm using this because no other question has been asked to solve for Q2 :)

A ball is thrown vertically upward. As it rises, what happens to its potential energy?​

Answers

Answer:

Explanation:

As the ball rises, its PE increases because the potential energy is equal to the mass of the ball times gravity times the height of the ball. The higher the height, the higher the PE.

Answer:

According to the law of conservation of energy its kinetic energy is getting converted in to potential energy because of gain in height. So, if the velocity of a ball goes on decreasing when it is thrown vertically upwards. When its velocity becomes zero, its potential energy becomes maximum.

A 25.0kg girl pushes a 50.0kg boy with a force of 100.0N. What is the acceleration of the girl?

Answers

Answer:

im pretty sure it should be 50.0

A mass that weighs 8 lb stretches a spring 24 in. The system is acted on by an external force of 4 sin 4t lb. If the mass is pulled down 6 in. and then released, determine the position of the mass at any time. Determine the first four times at which the velocity of the mass is zero

Answers

Answer:

[tex]t = \frac{\pi}{8}, \frac{\pi}{4}, \frac{3\pi}{8}, \frac{3 \pi}{4}[/tex]

Explanation:

The equation of force is

F = 4 sin 4 t

Compare with the standard equation

f = A sin wt

where, w is the angular frequency and A is the amplitude.

Now

w = 4 rad/s

Let the time period is T.

the relation for the time period is

[tex]T = \frac{2\pi}{w}\\\\T = \frac{2 \pi}{4}\\\\T = \frac{\pi}{2}[/tex]

the time period is defined as the time taken by the body to complete one oscillation.

So, the velocity is zero at the extreme points where the object is at time, T/4 and its odd T/2, 3T/4, 3T/2, etc.

So, the velocity is zero at time

[tex]t = \frac{\pi}{8}, \frac{\pi}{4}, \frac{3\pi}{8}, \frac{3 \pi}{4}[/tex]

An amoeba has 1.00 x 1016 protons and a net charge of 0.300 pC. Assuming there are 1.88 x 106 fewer electrons than protons, If you paired them up, what fraction of the protons would have no electrons

Answers

Answer:

The fraction of the protons would have no electrons [tex]=1.88\times 10^{-10}[/tex]

Explanation:

We are given that

Amoeba has total number of protons=[tex]1.00\times 10^{16}[/tex]

Net charge, Q=0.300pC

Electrons are fewer than protons=[tex]1.88\times 10^6[/tex]

We have to find the fraction of protons would have no electrons.

The fraction of the protons would have no electrons

=[tex]\frac{Fewer\;electrons}{Total\;protons}[/tex]

The fraction of the protons would have no electrons

=[tex]\frac{1.88\times 10^{6}}{1.00\times 10^{16}}[/tex]

[tex]=1.88\times 10^{-10}[/tex]

Hence, the fraction of the protons would have no electrons [tex]=1.88\times 10^{-10}[/tex]


[tex]what \: is \: reflection \: of \: light \: \: \: \: {?}[/tex]

Answers

Answer:

When a ray of light approaches a smooth polished surface and the light ray bounces back, it is called the reflection of light. The incident light ray which lands upon the surface is said to be reflected off the surface. The ray that bounces back is called the reflected ray.

The reservoir stores 6 500 000 m3 of water. The density of the water is 998 kg/m3. Calculate the mass of water in the reservoir. Give your answer in standard form.

Answers

Answer:

Mass = 64,870,000,000 kilograms

Explanation:

Given the following data;

Density = 998 kg/m³

Volume = 6,500,000 m³

To find the mass of water in the reservoir;

Density can be defined as mass all over the volume of an object.

Simply stated, density is mass per unit volume of an object.

Mathematically, density is given by the equation;

Density = mass/volume

Making mass the subject of formula, we have;

Mass = density * volume

Mass = 998 * 6,500,000

Mass = 64,870,000,000 kilograms

A bicycle and a car start their journey at the same time the cyclist reaches it's top speed of 10mls in 15 the car reaches a speed if 15 MLS in55 which has the greater acceleration the car or the bicycle

Answers

Complete question is;

A bicycle and a car start their journey at the same time the cyclist reaches it's top speed of 10m/s in 15 s, the car reaches a speed of 15 m/s in 55 s. which has the greater acceleration the car or the bicycle.

Answer:

The bicycle has the greater acceleration.

Explanation:

Cyclist reaches a top speed of 10m/s in 15 s.

Formula for acceleration here is;

a = v/t

a = 10/15

a = 0.67 m/s²

Car reaches a speed of 15 m/s in 55 s.

Thus;

a = 15/55

a = 0.27 m/s²

From the 2 acceleration values gotten, we can say that;

The bicycle has the greater acceleration.

A pair of forces with equal magnitude, opposite directions, and different lines of action is called a "couple." When a couple acts on a rigid object, the couple produces a torque that does not depend on the location of the axis. The drawing shows a couple acting on a tire wrench, each force being perpendicular to the wrench. Determine an expression for the torque produced by the couple when the axis is perpendicular to the tire and passes through the following. Express your answers in terms of the magnitude F of the force and the length L of the wrench.

Answers

The drawing shows the couple acting on a tire wrench is missing and so i have attached it.

We are to find an expression for the torque when the axis is perpendicular to the tire and passes through the points A, B & C

Answer:

Point A: τ = Fl

Point B: τ = 0

Point C: - Fl

Explanation:

Formula for torque is;

τ = F × d

Where;

F is perpendicular force

d is distance.

Thus;

> At point A, it means we are taking torque about point A and so we have;

τ = (-F × 0) + (F × L)

τ = Fl

> At point B, it means we are taking torque about point B and so we have;

τ = (-F × L/2) + (F × L/2)

τ = -(FL/2) + (FL/2)

τ = 0

> At point C, it means we are taking torque about point C and so we have;

τ = (-F × L) + (F × 0)

τ = -FL

What is this?
Picture

Answers

Answer:

may be upside down alphabet :"T"

Explanation:

Does this equation show that transmutation has taken place during decay?
Why or why not?
Ni – S.Ni+y
A. No, because there is conservation of the number of atoms as well
as the number of nucleons.
B. No, because high-energy electromagnetic waves are emitted.
C. Yes, because the numbers of nucleons and atoms are conserved.
D. Yes, because nickel atoms remain nickel atoms with the same
number of neutrons.

Answers

Answer:

Maybe A is the correct answer

What kind of waves are present during an earthquake?​

Answers

Body Waves - Primary (P) & Secondary (S) Waves.
Surface Waves - Rayleigh & Love Waves.

Answer:

There are four main types of earthquake waves:

P-waves S-waves (which are body waves), Rayleigh waves Love waves (which are surface waves).

HOPE IT HELPS!!

This question is divided into two parts. This is part (a) of the question. A proton accelerates from rest in a uniform electric field of 580 N/C. At some later time, its speed is 1.00 x 106 m/s. (a) Find the magnitude of the acceleration of the proton. (Mass of the proton is 1.67 x 10-27 kg and charge is 1.60 x 10-19 C) (in the following options 10^10 m/s^2 is 1010 m/s2)

Answers

Answer:

The acceleration of proton is 5.56 x 10^10 m/s^2 .

Explanation:

initial velocity, u = 0

Electric field, E = 580 N/C

final speed, v = 10^6 m/s

(a) Let the acceleration is a.

According to the Newton's second law

F = m a = q E

where, q is the charge of proton and m is the mass.

[tex]a= \frac{q E}{m}\\\\a = \frac{1.6\times10^{-19}\times 580}{1.67\times 10^{-27}}\\\\a= 5.56\times 10^{10} m/s^2[/tex]

The picture below shows a person swinging a yo-yo in a circle. Which vector shows the velocity of the yo-yo at this moment?
A. B
B. A
C. C
D. D

Answers

C, at this moment it is directly 90 degrees to the right and is only travelling downwards
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