018 10.0 points Calculate the average drift speed of electrons traveling through

Question

018 10.0 points Calculate the average drift speed of electrons traveling through a copper wire with a cross- sectional area of 90 mm* when carrying a cur rent of 99.9999 A (values similar to those for the electric wire to your study lamp). Assume one electron per atom of copper contributes to the current. The atomic mass of copper is 63.5 g/mol and its density is 8.93 g/cm Avogadro's number is 6.022 x 1023 and the fundamental charge is 1.602 x 10-19 C. Answer in units of m/s. 019 10.0 points A 121 V electric iron draws 4.99 A of current. How much heat is developed per hour? Answer in units of J.

Explanation / Answer

drift speed v = I/(n*e*A)

n = number free electrons per cubic meter

number of moles/m^3 = D/M = 8.93/63.5 = 0.1406 moles/cm^3 = 0.1406*10^6 moles/m^3

number of atoms N = 0.1406*6.022*10^23*10^6 atoms/m^3

number of free electrons per cubic meter n= N*1 = 8.467*10^28

dirft speed = 99.9999/(8.467*10^28*1.602*10^-19*90*(10^-3)^2) = 8.19 *10^-5 m/s

================================

heat developed Q = V*I*t

V = 121 V

I = 4.99 A

t = time = 1 hour = 3600 s

heat developed Q = 121*4.99*3600 = 2173644 J

Related Questions

Navigate

• Browse (All)
• Browse
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.