Question

A hollow ball with radius R = 2 cm has a charge of-4 nC spread uniformly over its surface (see the figure). The center of the ball is at P1=<-1, 0, 0> cm. A point charge of 6 nC is located at P3=<5, 0, 0> cm. (The diagram below is not drawn exactly to scale.)

What is the net electric field at location P2=<0,8,0>cm? 

At a particular instant an electron is at location P2. What is the net electric force on the electron at that instant?

What is the direction of the net electric force on the electron? 

• The force is opposite to the direction of the net electric field at P2 

• The force is in the same direction as the electric field at P2 

• The force is at right angles to the direction of the electric field at P2 

• There is not enough information to determine the direction of the force

Answer 1

You are very right with your electric field calculations and we know that F = qE where F is electric force and E is electric field at the given point. Now for electron q= -1.6* E-19 so for both the parts in F calculation you only have the sign mistake.

Fx = - 1.6*E-19 * -3902.69= 6.244*E-16 N

Fy = -1.6* E-19 * -350.53 = 5.608*E-17 N

Thanku