008 10.0 points A length of metal wire has a radius of 0.006 m and a resistance of 0.08 ?. When the potential di?erence across the wire is 16 V, the electron drift speed is found to be 0.000249 m/s. Based on these data, calculate the density of free electron in the wire. The fundamental charge is 1.6 × 10^ ?19 C. Answer in units of m^ ?3