Working with electrostatic force - unknown charge problem
A positive charge of 2X10-12 Coulombs placed 10cm from another charge experiences a repulsive force of 9X10-9 Newtons. What is the sign and magnitude of the other charge?
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SOLUTION This solution is FREE courtesy of BrainMass!
Since the charge experiences a repulsive force, the sign of the other charge is positive.
(same charges repells)
we have, F = AQ1q2/R^2 .....(1)
where A = 9x10^9
F = 9x10-9 N
Q1= 2x10-12 C
R = 10 cm = 10x10^-2m = 0.1m
R^2 = 0.01 m
from equation1 we get, q2 = F x R^2/A Q1
Substitute the values of the parameters,
q2 = [9x10-9 x0.01]/2x10-12 x 9 x 10^9
= (1/2) x 10^-11 x 10^12 x 10^-9
= 0.5 x 10^-8 Coulomb
The answer to the last posting is as follows sorry for the mistake
The charge of a proton is e= 1.6 x10^-19 coulomb
The force between two charges F = AQ1q2/R^2
where A = 9x10^9
Here we have for this equation,
1*10^-17 = 9x10^9 x 1.6 x10^-19 * 1.6 x10^-19 /R^2
therefore, R^2
= [9x10^9 x 1.6 x10^-19 * 1.6 x10^-19]/1*10^-17
=2.56 x 9 x 10^9 x 10^-21
Or the distance R = sqrt(25.6x10^-30) m
=4.8x10^-15 m
Answer
© BrainMass Inc. brainmass.com December 24, 2021, 4:47 pm ad1c9bdddf>https://brainmass.com/physics/work/working-electrostatic-force-unknown-charge-problem-7721