A cylindrical silver wire has a radius of 1.20 mm and a length of 1.30 m. A curr

Question

A cylindrical silver wire has a radius of 1.20 mm and a length of 1.30 m. A current of 1.00 A flows through the wire.

(a) What is the total number of grams of silver, which has a density of 10.49 g/cm3?

g

(b) What is the total number of conduction electrons? Assume there is one conduction electron per atom, and silver has a molecular weight of 107.87 g/mol.

electrons

(c) At 1.00 A, how long would it take to flow all of the electrons found in part (b) out of the wire?

s

(d) What is the drift velocity of the electrons, in m/s, defined as the average distance traveled divided by how long it takes?

m/s

Explanation / Answer

volume of the silver v = pi*r^2*l = pi*(1.2*10^-3)^2*1.3 = 5.88*10^-6 m^3

mass of silver = m = D*v = 10.49*10^3*5.88*10^-6 = 61.68 g

------------------

(b)

molecular weight M = 107.87 g/mol

number of moles = m/M

number of atoms = (m/M)*N

N = avagadro number = 6.023*10^23

number of atoms = (61.68/107.87)*6.023*10^23 = 3.44*10^23

number of electrons n = 3.44*10^23

---------------

(c)

current i = q/t

t = n*e/i = (3.44*10^23*1.6*10^-19) = 55040 s

-------------------

(d)

drift velocity = v = l/t = 1.3/(55040)

v = 23.62 um/s   <<<_----------answer

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

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