ok i have no idea, copper has oe free electron per atom, the number density of atoms in a sample of copper is 2.1x10^29 m^-3.
The charge of the electron is 1.6x10^-19C
The current in a copper wite of diameter 1.2mm is 7.2A
Caculate the drift speed of the free electrons

Question

ok i have no idea, copper has oe free electron per atom, the number density of atoms in a sample of copper is 2.1x10^29 m^-3.
The charge of the electron is 1.6x10^-19C
The current in a copper wite of diameter 1.2mm is 7.2A 
Caculate the drift speed of the free electrons

jamesj · Answer

Think of this like a water hose now.  The current I tells you how fast the water is coming out.  I.e., the amount of charge.

How much charge comes out in 1 second?

jamesj · Answer

Call that number C.

The calculate what volume of Copper is required to deliver that amount of charge.

jamesj · Answer

$$ C = It = 7.2 \ Coulomb $$

jamesj · Answer

In one cubic meter of copper we have 2.1 x 10^29 free electrons.  How many Coulomb of charge is that?

jamesj · Answer

Each electron has a charge of 
e = 1.6 x 10^-19 Coulomb

Hence the charge of the free electrons in 1 cubic meter of copper is ... what?

anonymous · Answer

i think i need to read my book again lol this is very confusing to me

jamesj · Answer

ok

anonymous · Answer

thanks for the help though