Question

A cell membrane has a resistance and a capacitance and thus a characteristic time constant

Part A

What is the time constant of a 7.7 nm -thick membrane surrounding a 4.0×10⁻² mm -diameter spherical cell? Assume the resistivity of the cell membrane as 3.6×106 Ω⋅m and the dielectric constant is approximately 9.0.

Express your answer to two significant figures and include the appropriate units.

Answer 1

THERE IS NO FIGURE IN THE QUESTION TO INDICATE THE DIRECTION OF MAGNETIC FIELD...

how ever to find the direction of magnetic field the below formula is used

The Lorentz force, F = q(v x B), where q = electric charge, v = velocity of the charge particle, and B = magnetic field.

The direction of the charge particle is determined by v. F, v, and B are vectors, and follow the right-hand rule. First, point your right arm straight in the direction the particle is traveling, palm/hand flat with the thumb pointing at a right angle to the other 4 fingers; second, curl your right hand (bend at the wrist) toward where the magnetic field is pointing. The thumb indicates the direction of the force.

For example, assume the magnetic field is pointing perpendicularly out of this page (a plane) toward you. Assume the charge particle carries a positive charge and is traveling up the page in the beginning. Then the force acts on the particle as a centripetal force and pulls the particle toward the right. The net result is that, in an ideal situation, the particle rotates in a clockwise direction on the plane. A negative particle will do so in a counterclockwise fashion