Question

A 7.80-nC charge is located 1.70 m from a 4.30-nC point charge.

(a) Find the magnitude of the electrostatic force that one charge exerts on the other.

Answer in N

(b) Is the force attractive or repulsive?

Answer 1

Given data is..

Current Charge q₁=7.80 nC=7.80*10^-9 C

Radius r=1.70m

Point Charge q₂=4.30 nC=4.30*10^-9 C

Now

• Find the magnitude of the electrostatic force that one charge exerts on the other.
• Is the force attractive or repulsive?

(a) From the coulomb's law we can find Magnitude of the Electrostatic Force

coulomb's equation is   

Here where is the separation distance and is Coulomb's constant. K_e=8.98*10⁹ N.m².C^-2

substitute all values in the above eqbation we get Force value...

F=(8.98*10⁹)(7.80*10^-9 )(4.30*10^-9 C) / (1.70)²

F=301.189*10^-9 / (2.89)

F=104.21*10^-9 N=0.104*10^-6 N

(b) From the coulomb's law

"If the product is positive the force between the two charges is repulsive; if the product is negative, the force between them is attractive".

Here the product is in positive sign then force is repulsive direction only.