Why are action potentials usually conducted in one direction?

In a system, when potential energy decreases, then entropy also decreases. true false

Four friends, a, b, c, and d are standing varying distances away from a speaker which is producing sound waves.

Abeam of electrons moves at right angles to a magnetic field of 4.5 × 10-2 tesla. if the electrons have a velocity of 6.5 × 106 meters/second, what is the force acting on the electrons? the value of q = -1.6 × 10-19 coulombs.