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Isaac Physics MicroScopic Current Question:

Here is the link with all information:

I've done part A, part B but I need help with parts C, D and E.
Original post by OOOllie
Here is the link with all information:

I've done part A, part B but I need help with parts C, D and E.

I cannot see any link to the question.
Part c is asking for the average drift velocity
displacement = 35 cm
time taken = 30 minutes (or 30 x 60 = 1800 sec)

v=s/t

The question explains that the drift velocity is likely to be very small
Reply 4
Thank you so much but what about the rest, I was using the actual drift velocity equation
Reply 5
Original post by OOOllie
Thank you so much but what about the rest, I was using the actual drift velocity equation

So what about parts D and e :P
Original post by OOOllie
So what about parts D and e :P


D and E are related.

For D, (IMO) it is a matter of whether you know the formula of current density which is

J=nqvd J = nqv_d

For E, use the definition of current density which is the current per unit area of cross section of the wire

J=IA J = \dfrac{I}{A}
It would be good that you go through this webpage to understand the concepts introduced in this problem.
http://hyperphysics.phy-astr.gsu.edu/hbase/electric/ohmmic.html
Reply 8
so I've got the number density as 8.49x10^22 cm3 and 0.019 cm/s so then I converted to get into m and I got 8.49x10^16 and 0.00019
Then because of that I did 8.49x10^16x1.6x10^-19x0.00019 but yet still didn't get it right
Original post by OOOllie
so I've got the number density as 8.49x10^22 cm3 and 0.019 cm/s so then I converted to get into m and I got 8.49x10^16 and 0.00019
Then because of that I did 8.49x10^16x1.6x10^-19x0.00019 but yet still didn't get it right


Number density is 8.49E22 cm-3 NOT 8.49E22 cm3.
The conversion to m-3 or m3 is different.
Reply 10
Oooo how do you convert it then?
Original post by OOOllie
Oooo how do you convert it then?



8.49×10221 cm3=8.49×10221 cm×1 cm×1 cm=8.49×10220.01 m×0.01 m×0.01 m \dfrac{8.49 \times 10^{22}}{1 \text{ cm}^3} = \dfrac{8.49 \times 10^{22}}{1 \text{ cm} \times 1 \text{ cm} \times 1 \text{ cm}} = \dfrac{8.49 \times 10^{22}}{0.01 \text{ m} \times 0.01 \text{ m} \times 0.01 \text{ m}}

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