(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

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?

2. Relevant equations

F = k q1q2/r^2

N= Q/e

k = 8.99E9 nm^2/c^2

e= -1.602E-19C

3. 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 :/

1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Coulomb's Law & Electrons

**Physics Forums | Science Articles, Homework Help, Discussion**