Drift speed

  • Thread starter GreenDinos
  • Start date
  • #1
10
0
A silver wire of diameter 1 mm carries a current of 130 mA. The density of conduction electrons in silver is 5.8X10^28 m-3. How long (on average) does it take for a conduction electron to move 1.0 cm along the wire?

ok, so first I calculated drift speed using the equation Vd = I/ Ne * A

for Area, I just used pi*r^2

I set it up Vd = .130A/ ((5.8e28 m^-3) x (7.853e-7 m^2)) and got the drift speed to be 2.8538e-24 m/s

I then set up 2.8538e-24 m/s x 100cm/m x 60sec/min and got
1.71228e-20cm/ min .

To get minutes for one cm i took
1cm/1.71228e-20cm/ min and got 5.840e19 minutes to move one cm.

i'm obviously doing somehting wrong because it's not accepting my answer. Is there something I'm missing??
 
Last edited:

Answers and Replies

  • #2
ehild
Homework Helper
15,543
1,914
GreenDinos said:
A silver wire of diameter 1 mm carries a current of 130 mA. The density of conduction electrons in silver is 5.8X10^28 m-3. How long (on average) does it take for a conduction electron to move 1.0 cm along the wire?

ok, so first I calculated drift speed using the equation Vd = I/ Ne * A
You left out the charge of the electrons. Neglecting signs,
[tex] v_d=\frac{I}{A q N_e}\mbox{ , q = }1.6\cdot10^{-19}\mbox{ C. }[/tex]

ehild
 

Related Threads on Drift speed

  • Last Post
Replies
1
Views
1K
  • Last Post
Replies
6
Views
1K
  • Last Post
Replies
1
Views
11K
  • Last Post
Replies
2
Views
1K
  • Last Post
Replies
3
Views
8K
  • Last Post
Replies
1
Views
4K
  • Last Post
Replies
3
Views
10K
  • Last Post
Replies
1
Views
12K
  • Last Post
Replies
2
Views
2K
  • Last Post
Replies
5
Views
1K
Top