Apoint charge with charge q1 = 2.10 μc is held stationary at the origin. a second point charge with charge q2 = -4.60 μc moves from the point ( 0.110 m , 0) to the point ( 0.275 m , 0.240 m ). how much work w is done by the electric force on the moving point charge? express your answer in joules. use k = 8.99×109 n⋅m2/c2 for coulomb's constant: k=14πϵ0.

Work done is - 0.552 J, i.e 0.552 J of work is done by the force.

Solution:

As per the question:

Charge,

Charge,

The point P is at (0.110 m, 0)

The point Q is at (0.275 m, .240 m )

k =

Now,

Work done on moving a charge is given by the change in its potential energy:

W =

Now, the electrostatic potential energy is given by:

where

R = Distance between the charges.

Now,

Initial PE, at point P(0.110 m, 0) from origin:

Similarly, at point Q(0.275 m, 0.240 m) from origin:

Work done, W =

electric field is a function of 1/r^2

yes, the force per unit charge for a point charge is inverse square law.