Question

2. Suppose you have a number of charges, greater than two (for example, 4). The first charge is located somewhere and suppose it is held in place. How much work is done to bring the second charge in from infinity to its final location? Now hold that charge fixed as well and bring in the third charge, how much work is done? Now hold the third charge fixed in place as well and bring in the fourth charge, how much work is done? What is the total for establishing the configuration of the four charges?

3. The electrostatic potential is defined as V = U/q (the potential energy per unit charge). Sketch the potential curves as a function of r for point charges (both positive and negative ) located at the origin. How is the force on a test charge placed in the potential of one of the above charges related to the slope of the potential curve? Explain your rationale. Why must the potential curve be continuous?

4. From the definition of potential ∆U =q ∆V. If a charge is accelerated across a potential difference of ∆V how is the change in kinetic energy of the charge related to ∆V? Why?

Answer 1