If the current direction in the metal wire AB is from a to B, then the direction of the free electrons in the wire is from a to B___ To___ ．

If the current direction in the metal wire AB is from a to B, then the direction of the free electrons in the wire is from a to B___ To___ ．

We stipulate that the direction of current is the same as that of positive charge, but opposite to that of negative charge

What is the difference between the thermal motion rate of free electrons, the conduction rate of current and the moving rate of free electrons

In a metal conductor, the thermal motion rate of free electrons is very high, about 100000 meters per second. It is an attribute of electrons. The conduction rate of electric current is about the speed of light. This is also because when a voltage is applied to the conductor, a constant electric field is rapidly established at each position in the circuit. Under the action of this electric field, the free electrons everywhere in the circuit almost

If the wire is uniformly elongated to 1 / 2 of the original cross section radius, and the voltage U is still applied at both ends, the directional movement rate of the electron is?

According to the principle of volume invariance and the formula of S = π R ^ 2, the length of the conductor is 4 times of the original, and the cross-sectional area is 1 / 4 of the original, that is, l '= 4L, s' = s / 4. According to Ohm's law, I = u / R and R = ρ L / s, the current is 1 / 8 of the original, that is, I' = I / 8