1. How much work must be done to bring three electrons from a great distance apart to within m from one another?

2. A parallel-plate capacitor is isolated with a charge Q on each plate.
If the separation of the plates is halved and a dielectric (constant K) is inserted in place of air, by what factor does the energy storage change?
To what do you attribute the change in potential energy?
How does the new value of the electric field between the plates compare with the original value?

3. Electric Currents

4. The Electric Battery

5. Electric Cell

6. Electric Current

7. When a continuous conducting path is connected between the terminals of a battery, we have an electric circuit.

8. When such a circuit is formed, charge can flow through the wires of the circuit, from one terminal of the battery to the other. A flow of charge such as this is called as electric current.

9. Units of Current
1 Ampere (A) = 1 C /1 s

10. Conceptual Example: How to Connect a Battery.
What’s wrong with each of circuits shown below?

11. Conventional Current

12. When we speak of the current flowing in a circuit, we mean the direction positive charge would flow.

13. Important: Current is not a vector, it’s a scalar!!!!

14. Important : In any single circuit, the current at any instant is the same at one point as at any other point!!! This follows from the conservation of electric charge.