Question

Two point charges lie on the x-axis. A charge of 6 uc is at the origin and a charge -10 uc is at x=10cm.

A.) Find the magnitude and the direction of the force on the 6-uC charge.

B.) Find the mangnitude and the direction of the net electric field at a point x=4cm.

C.) Find the voltage at point x=4cm.

Answer 1

(A) Magnitude of Force F between two charges q1 and q2 is given by

    (assuming air as medium in which charges are present)

    ( taking only magnitude of force)

F=54 N    (both charges will apply this force on each other)

direction of force at 6 C, as charges are of opposite nature force will be attractive and will act along x axis .

(B) Electric field at point due to charge q given by

Electric field due to 6 C charge at 4cm distance.

      

E1=3.37x10³ N/c   ( along x axis)

Electric field due to -10 C charge at (10 - 4) =6cm distance.

E2= - 2.5x10³ N/c   ( negative sign only shows direction along negative direction of x axis)

both field are in opposite directio hence angle between E1 and E2 is 180^o hence net field at that point is given by

E=(E1 - E2)

=3.37x10³- 2.5x10³

E= 870 N/c ( direction of net field is along positive direction of x axis )

(c) potential at x=4cm

electric potential due to charge q at a distance is given by relation

potential due to both charge are                      (as potential is a scalar quantity we can use algebric rules )

  

V= - 1.5x10⁵ volt (ANS)

(distance from -10 C side is 6cm )