Question

problem

A wire 4.00 m long and 6.00 mm in diameter has a resistance of 15.0 m2. A potential difference of 22.0 v is applied between the ends Resistivity, p Temperature Coefficient of Resistivity, a(K-1) Material (2 m) Typical Metals 41 x 10-3 Silver 1.62 x 10 43 x 10-3 1.69 x 10 Copper 40 x 10-3 2.35 x 10-8 Gold 4.4 x 10 2.75 x 10 Aluminum 4.82 x 10-s 0.002 x 10-3 Manganin 4.5 x 10-3 5.25 x 10 s Tungsten 6.5 x 10-3 9.68 x 10 106 x 10-s 3.9 x 10-3 Platinum "An alloy specifically designed to have a small value of a (a) What is the current in the wire? X A Enter umber (b) What is the current density?

Answer 1

A)Current= V/R
      =22/0.015
       =1466.67 A
B)
Currrent density=current/area
              =1466.67/(pi*0.003^2)
              =51872722.19 A/m^2

Answer 2

a)

I = V/R = 22/(15X10^-3) = 1.4666 X10^3 A = 1466.66 A

2)

area = 3.14 X(3^2)X(10^-6) m^2 = 28.26 X10^-6

current density = current/area = 1466.66/28.26X10^-6 = 51.898 X 10^6 A/m^2 = 518990327.905 A/m^2