Question

A current-carrying conductor made of aluminum gradually narrows as shown in the figure below. The cross-sectional area of region 1 is twice that of region 2. In region 1, the current is 7.55 mA and the current density is 3.80 kA/m^2. Find the drift speed in both regions of the conductor. Region 1 Your response differs from the correct answer by more than 10%. Double check your calculations, m/s Region 2 m/s

Answer 1

current density J = I/A

in region 1

J1 = I/A1

A1 = I/J1

dirft speed v1 = I/(n*e*A1)

v1 = I*J1/(n*e*I) = J1/(n*e)

I = current in the conductor

n = electron density = 6*10^28

v1 = 3.8*10^3/(6*10^28*1.6*10^-19)

v1 = 3.95*10^-7 m/s

in region 2

A2 = A1/2 = I/(2*J1)

v2 = 2*J2/(n*e) = 2*3.8*10^3/(6*10^28*1.6*10^-19)

v2 = 7.92*10^-7 m/s