1. Example 25.1: A proton, of mass 1.67×10 -27 Kg, enters the region between two parallel plates a distance 20 cm apart. There is a uniform electric field of 3 × 10 5 V/m between the plate, as shown in Fig25.6 If the initial speed of the proton is 5 × 10 6 m/s, what is its final speed?

2. Example 25.2:Three point charges q 1 =1 μ C, q 2 =-2 μ C, and q3=3 μ C are fixed at the positions shown in Fig. 25.13a (a) What is the potential at point p at the corner of the rectangle? (b) How much work would be needed bring a charge q 4 =2.5 μ C from infinite and to place it at p? (c) What is the total potential energy of q 1,q 2 and q 3 ?

3. EXAMPLE 25.3: In 1913, Niels Bohr proposed a model of the hydrogen atom in which an electron orbit a stationary proton in a circular path. Find the total mechanical energy of the electron given that the radius of the orbit is 0.53 × 10 -10 m

4. Example 25.4:The potential due to a point charge is given by V=kQ/r. Find: (a) the radial component of the electric field; (b) the x component of the electric field.

5. Example 25.5: A nonconducting disk of radius a has uniform surface charge density σC/m 2. What is the potential at a point on the axis of the disk at a distance y from its center?

6. Example 25.6:A shell of radius R has a charge Q uniformly distributed over its surface. Find the potential at a distance r>R from its center.

7. Example 25.7: A metal sphere of radius R has a charge Q. Find its potential energy.

8. DISCUSSION RQ ELECTRIC POTENTIAL I,II

9. Exercises of chapter 25 Questions: 7,9,15 Exercises:5,11,35,46,48,50,53,58 Problems:5,6,7,9,11,12,16