The resistivity of gold is 2.44×10−8Ω⋅m at room temperature. A gold wire that is 0.9 mm in diameter and 14 cm long carries a current of 940 mA. What is the electric field in the wire

0.03605 V/m is the electric field in the gold wire.

Explanation:

Resistivity of the gold =

Length of the gold wire = L = 14 cm = 0.14 m ( 1 cm = 0.01 m)

Diameter of the wire = d = 0.9 mm

Radius of the wire = r = 0.5 d = 0.5 × 0.9 mm = 0.45 mm =

( 1mm = 0.001 m)

Area of the cross-section =

Resistance of the wire = R

Current in the gold wire = 940 mA = 0.940 A ( 1 mA = 0.001 A)

( Ohm's law)

We know, Electric field is given by :

0.03605 V/m is the electric field in the gold wire.