Lectric field of axons. a nerve signal is transmitted
through a neuron when an excess of na+ ions suddenly
enters the axon, a long cylindrical part of the neuron. axons are
approximately 10.0 mm in diameter, and measurements show that
about 5.6 * 1011 na+ ions per meter (each of charge +e) enter
during this process. although the axon is a long cylinder, the charge does not all enter everywhere at the same time. a plausible
model would be a series of point charges moving along the
axon. consider a 0.10-mm length of the axon and model it as a
point charge. (a) if the charge that enters each meter of the axon
gets distributed uniformly along it, how many coulombs of charge
enter a 0.10-mm length of the axon? (b) what electric field (magnitude
and direction) does the sudden influx of charge produce
at the surface of the body if the axon is 5.00 cm below the
skin? (c) certain sharks can respond to electric fields as weak as
1.0 mn> c. how far from this segment of axon could a shark be
and still detect its electric field?