An average nerve axon is about 4x10-6m in radius, and the axoplasm that composes the interior of the axon has a resistivity of about 2.3 ω ⋅m.

what is the resistance of just 2-cm length of this axon?

provide your answer in mega-ohms (1 mega-ohm = 106 ohms or "millions of ohms").

(note, this value is so large -- it corresponds to the resistance of tens of thousands of miles of the thinnest copper wire normally -- that it explains why a nerve pulse traveling down an axon cannot simply be a current traveling along the axon. the voltage required to achieve a perceptible current in the axon would have to be gigantic! we will investigate how voltage pulses -- not current -- travel down axons in a future lab.)

The membrane surrounding a living cell consists of an inner and an outer wall that are separated by a small space. assume that the membrane acts like a parallel plate capacitor in which the effective charge density on the inner and outer walls has a magnitude of 7.0 × 10-6 c/m2. (a) what is the magnitude of the electric field within the cell membrane? (b) find the magnitude of the electric force that would be exerted on a potassium ion (k+; charge = +e) placed inside the membrane.

Aparticle of mass m is projected with an initial velocity v0 in a direction making an angle α with the horizontal level ground as shown in the figure. the motion of the particle occurs under a uniform gravitational field g pointing downward. (a) write down the lagrangian of the system by using the cartesian coordinates (x, y). (b) is there any cyclic coordinate(s). if so, interpret it (them) physically. (c) find the euler-lagrange equations. find at least one constant of motion. (d) solve the differential equation in part (c) and obtain x and y coordinates of the projectile as a function of time. (e) construct the hamiltonian of the system, h, and write down the hamilton’s equations (canonical equations) of motion.

What type of relationship exists between the length of a wire and the resistance, if all other factors remain the same? o a. resistance is directly related to length. ob. resistance is directly related to the square of the length. c. resistance is inversely related to the length. d. resistance is inversely related to the square of the length. reset next