Current Question: How Many Electrons in Copper Wire/sec?

[cremedelacreme]

A copper wire of cross sectional area 2 mm^2 carries a current of 10 A. How many electrons pass through a given cross sectional of the wire in one second?

 

[Doc Al]

What's the definition of current?

 

[cremedelacreme]

Err V= IR?

But I don't know how to relate with Area...

 

[Doc Al]

Err V= IR?

Nope. That's Ohm's law. Hint: What does the unit Ampere mean? 1 A = ??

But I don't know how to relate with Area...

Perhaps the area is irrelevant.

 

[cremedelacreme]

Err

Ampere = Charge / Time
So

Charge = Ampere / Time

ooh
we find the charge
and since
one electron has a charge of 1.6 x 10^-19
thus, we divide the charge by the charge of one electron...

is it correct?

 

[Doc Al]

Ampere = Charge / Time

Right!

So

Charge = Ampere / Time

Careful: If Current = charge/time then charge = current * time.

ooh
we find the charge
and since
one electron has a charge of 1.6 x 10^-19
thus, we divide the charge by the charge of one electron...

Good!