Question

A wire 3.31 m long and 6.32 mm in diameter has a resistance of 12.1 mΩ. A potential difference of 27.8 V is applied between the ends. (a) What is the current in amperes in the wire? (b) What is the magnitude of the current density? (c) Calculate the resistivity of the material of which the wire is made.

Answer 1

Given is:-

Length = 3.31m

Diameter = 6.32 mm

Resistance =   or

Ptential V= 27.8 volts

Now,

Part-a

The current across a resistor is given by

plugging all the values we get

Part-b

The current density is given by

(A is the cross sectional area)

which gives us

Part-c

Resistance is given by

by plugging all the values we get

which gives us the resistivity of the material of the wire