How Many Electrons Generate the Charge in Coulomb's Law Problem?

[kgigs6]

Homework Statement

Two spherical objects are separated by a distance of 1.98 x 10-3 m. The objects are initially electrically neutral and are very small compared to the distance between them. Each object acquires the same negative charge due to the addition of electrons. As a result, each object experiences an electrostatic force that has a magnitude of 4.19 x 10-21 N. How many electrons did it take to produce the charge on one of the objects?

Homework Equations

F = k q1q2/r^2

N= Q/e

k = 8.99E9 nm^2/c^2
e= -1.602E-19C

The Attempt at a Solution

I used coulomb's law and plugged in the Force as 4.19E-21N, boltsmans constant for k and 1.98E-3m as the r^2.

4.19E-21N = (8.99E9Nm^2/C^2)(q^2)/(1.98E-3)^2
1.642E-26N/m^2 = (8.99E9Nm^2/C^2)(q^2)
q = sqrt(1.82719E-36)
q= 1.3517E-18C

N= Q/e
N= (-1.3517E-18C)/(-1.602E-19C)
N= 8.43781 electrons

I've done this over and over and get the same answer but it tells me I'm wrong and I'm not sure what else to try :/

 

[Delphi51]

I got the same thing independently. Looks like there is an error in the question.

 

[kgigs6]

Thanks for your help, It's good to know I'm not crazy hah