A cell membrane consists of an inner and outer wall separated by a distance of approximately 10nm. Assume that the walls act like a parallel plate capacitor, each with a charge density of 10?5C/m2, and the outer wall is positively charged. Although unrealistic, assume that the space between cell walls is filled with air.

PART A. What is the magnitude of the electric field between the membranes?

1×106N/C

1×10?15N/C

5×10?5N/C

9×10?2N/C

PART B. What is the magnitude of the force on a K+ ion between the cell walls?

2×10?13N

9×10?13N

2×10?11N

3×10?12N

PART C. What is the potential difference between the cell walls?

6×10?3V

1×107V

10V

1×10?2V

A) 1×10^6N/C

B) 2×10^-13N

C) 1×10^-2v

Explanation:

For parallel plates,the electric field E is given by:

E=s/eo

Where s= surface charge density

E = 10^-5/8.85×10^-12

E= 1.13×10^6 approximately 1×10^6NC^-2

B) Na has a charge of 1.6×10^-19

F= q×E= (1.13×10^6) × (1.6×10^-19)

F= 1.8×10^-13 approximately 2×10^-13N

C) Potential difference ,V= E×d

d=10nm=10^-8

V= 1.13×10^6 ×10^-8

V = 1.13×10^-2 approximately 1x10^-2v

force is based upon mass and acceleration.the statement is not always true.

it can be explained from newton's second law of motion.

as per newton's second law of motion the rate of change of momentum is directly proportional to the applied force and takes place along the direction of force.

mathematically it can be written as -

                                              ⇒      

here   k is the proportionality constant whose value is 1.

                                                            [a is the acceleration=dv/dt]

hence we see that force not only depends on mass and acceleration but also on velocity and rate of change of mass. force f will depend on mass and acceleration only when mass is constant.

hence the statement that force is based upon mass and acceleration is false.