Step-by-step explanation:
Given that,
Mass of Nichrome, m = 0.5 g
The resistance of the wire, R = 0.673 ohms
Resistivity of the nichrome wire,

Density,

(A) The length of the wire is given by using the definition of resistance as :
Volume,

Area,
....(1)

(b) Equation (1) becomes :

Hence, this is the required solution.