A 1.2m copper wire with a 2.5mm diameter has a 1.5V potential difference across its ends. The electric field inside the wire is 1.3 N/C. The current density is 7.3x10^7 C/m^3. It takes an electron 2.6x10^-25 seconds to drift from one end of the wire to the other.

1. A copper wire 1.2 m long with a diameter of 2.5 mm has a potential difference of 1.5 V across its
ends What is the magnitude of the electric field inside the wire? Answer 1.3NIC Check Correct
Marks for this submission: 2.00/2.00 What is the current density in the wire? Answer 7.3e7C/M
3 Check You did not give the correct unit. Partially correct Marks for this submission: 1.80/2.00
How long does it take an electron at one end of the wire to drift to the other end of the wire?
Answer2.6e-25S Check
Solution
Drift speed of electron in copper = mobility of electron in copper x electric field applied
Hence speed = 4.5 x 10^-3 x 1.3 = 5.85 x 10^-3 m/s
Time = distance/ speed = 1.2/ speed = 205.13 seconds
Hence time required for an electron to move from one end to another end of wire is 205.13
seconds
Also the unit of current density is Amp/m^2