Physics. Free electron density, please help!
posted by samantha .
A length of wire has a radius of 3.00 × 103 m and a resistance of 0.200 Ω. When the potential difference across the wire is 10.0 V, the electron drift speed is found to be 2.98 × 104 m/s. On the basis of these data, calculate the density of free electrons in the wire.
Your help is much appreciated! :)

Compute the current I using Ohm's law.
The flux of free electrons F is the free electron density tomes the drift velocity v. If you multiply this flux by the electron charge and the cross section, you get the current. By equating this with what you get from Ohm's law, you can thus solve for the free electron density. 
Call the free electron density N, m^3
e = electron charge , Coulombs
V = electron drift speed
I = current, Amps
A = cross sectional area, pi r^2, m^2
I = N*A*e*V
Solve for N in this case.
Get the current I from ohms law. I = V/R
Respond to this Question
Similar Questions

College Physics
How do I solve this problem: A particular wire has a current of 10A. A) How many electrons pass a fixed point every 5 seconds? 
Physics
Two wires with the same resistance have the same diameter but different lengths. If wire 1 has length L1 and wire 2 has length L2, how do L1 and L2 compare if wire 1 is made from copper and wire 2 is made from aluminum? 
Physics
Calculate the resistance per unit length of a nichrome wire, which has a radius of 0.436 mm. The resistivity of nichrome is 1.5×10−6 Ω·m. Answer in units of Ω/m If a potential difference of 20 V is maintained across … 
physics
A length of wire has a radius of 3.00 ~ 103 m and a resistance of 0.200 ƒ¶. When the potential difference across the wire is 10.0 V, the electron drift speed is found to be 2.98 ~ 104 m/s. On the basis of these data, calculate … 
university, physics.
A length of wire has a radius of 3.00 ~ 103 m and a resistance of 0.200 ƒ¶. When the potential difference across the wire is 10.0 V, the electron drift speed is found to be 2.98 ~ 104 m/s. On the basis of these data, calculate … 
physics, university
A length of wire has a radius of 3.00 x 103 m and a resistance of 0.200 ohms. When the potential difference across the wire is 10.0 volts, the electron drift speed is found to be 2.98 x104 m/s. On the basis of these data, calculate … 
physics
As part of a class project you are given 0.900 g of nichrome and asked to fabricate a wire with uniform crosssection. You use up 95% of the nichrome and make a wire with a resistance of 0.840 Ω. The resistivity of nichrome is … 
Physics
A piece of copper wire has a resistance per unit length of 5.50 x 10^3 Ω/m. The wire is wound into a thin, flat coil of many turns that has a radius of 0.200 m. The ends of the wire are connected to a 12.0V battery. Find the … 
Physics 
Q.1. Two wires each of length 40 m and diameter 2.6 mm, are connected in series. A potential difference of 50 V is applied between the ends of the composite wire. The resistances the wires are 0.13 Ω and 0.75 Ω, respectively. … 
physics
A copper wire that has a diameter of 2.9 mm carries a current of 39.0 A. Assuming that each copper atom contributes one free electron to the metal, find the drift velocity of the electrons in the wire. The molar mass of copper is 63.5 …