The diagram above shows two wires; wire 1 and wire 2. The charge carriers in wir
ID: 2290287 • Letter: T
Question
The diagram above shows two wires; wire 1 and wire 2. The charge carriers in wire 1 (of circular cross section and radius R) have a drift speed down the wire that is not constant across the wire. Instead, the drift speed rises linearly from zero at the circumference (r R) to y0 at the center (r 0), according to vd(r) = v0(1-r/R). A second wire (wire 2) has the same radius, the same density of charge carriers and a constant drift speed given by vd (r) = f*v0. Evaluate the ratio of the current carried by wire 1 to the current carried by wire 2, when f 0. 400.Explanation / Answer
in this question current is propotional to area of crosssection of conductor and drift velocity
so integrate with respect to r in first part of equation
from limits r=0 to r=R
current in the first wire as I1=kxv0xR^3/2
current in second wire is I2=KXV0XR^3XF
I1/I2 =1/2F =1/2X0.4
=1.25