A current of I = 3.8 A is passing through a conductor with cross sectional area A = 2.5 x 10^-4 m^2. The charge carriers in the conductor, electrons, have a number density n = 1.3 x 10^27 m^-3.
(a) Express the drift velocity of electrons through 1.A. n, and the fundamental charge e.
(b) Calculate the numerical value of v, in m/s.

Explanation:

current, i = 3.8 A

Area of crossection, A = 2.5 x 10^-4 m²

number density, n = 1.3 x 10^27 m^-3

(a) the relation between the current and the drift velocity is given by

i = n e A v

where, e is the electronic charge, A be the area of crossection area of the wire and v be the drift velocity

v = i / neA

(b)

3.8 = 1.3 x 10^27 x 1.6 x 10^-19 x 2.5 x 10^-4 x v

3.8 = 52000 v

v = 7.3 x 10^-5 m/s

object 2 because all the other ones are wrong

the total distance that martina travels that day is

(distance from home to mom's office) plus (distance from mom's office to school)

plus (distance from school to library) plus (distance from library to friend's house)

plus (distance from friend's house to martina's house).

(we don't know what any of these distance actually is.)