How long does it take electrons to get from a car battery to the starting motor? assume the current is 260 a and the electrons travel through a copper wire with cross-sectional area 0.200 cm2 and length 1.00 m. the number of charge carriers per unit volume is 8.49 × 1028 m-3.

17.41 minutes

Explanation:

i = 260 A

A = 0.2 cm^2 = 0.2 x 10^-4 m^2

l = 1 m

n = 8.49 x 10^28 per cubic meter

Let the drift velocity is vd.

The relation between the current and the drift velocity os given by

i = n e A vd

260 = 8.49 x 10^28 x 1.6 x 10^-19 x 0.2 x 10^-4 x vd

vd = 9.57 x 10^-4 m/s

Let the time taken be t

time = distance / speed

t = l / vd = 1 / (9.57 x 10^-4) = 1044.93 seconds = 17.41 minutes

work: w = fd (given)

work done by chet   =50*1 = 50 j

work done by mika =40*2 = 80 j

work done by sara =30*1.5 = 45 j

work done by bill =60*0.5 = 30 j

students in order from the greatest amount of work done to the least is mika> chet> sara> bill

hence option (b) is correct.

0.11 m/s and 0.28 m/s should be correct