Three point charges,two positive and one negative,each having a magnitude of 20 $\mu$C are placed at the vertices of an equilateral triangle (30 cm on a side).What is the magnitude of the electrostatic force on the negative charge?
A)80 N
B)40 N
C)69 N
D)57 N
E)75 N

Question

Quizplus · Accepted Answer

The electrostatic force on the negative charge can be found by taking the vector sum of the forces due to the two positive charges. By symmetry, we know that the angle between the two forces is 60 degrees. We can use Coulomb's law to find the magnitude of each force:

F = kq1q2/r^2

where k is Coulomb's constant, q1 and q2 are the magnitudes of the charges, and r is the distance between them.

Since the charges are all the same magnitude, we have:

F = kq^2/r^2

Plugging in the given values, we get:

F = (9 x 10^9 Nm^2/C^2) x (20 x 10^-6 C)^2 / (0.3 m)^2 
F = 69 N

Therefore, the magnitude of the electrostatic force on the negative charge is 69 N.

Three Point Charges,two Positive and One Negative,each Having a Magnitude μ\muμ

Three Point Charges,two Positive and One Negative,each Having a Magnitude $\mu$