Chapter 17
1. (p.522 prob.8) Two parallel plates, connected to a 100-V power supply, are separated by an air gap. How small can the gap be if the air is not to exceed its breakdown value of E = 3 x 103V/m?
2. (p.522 prob.9) The work done by an external force to move a -7.50mC chaarge from point a to point b is 2.50 x 10-4J. If the charge was started from rest and had 4.82 x 10-4J of kinetic energy when it reached point b, what must be the potential difference between a and b.
3. (p.522 prob.15) A +30mC charge is placed 32cm from an identical +30mC charge. How much work would be required to move a + 0.5mC charge from a point midway between them to a point 10cm closer to either of the charges?
4. (p.524 prob.37) An electric field of 8.50 x 10V/m is desired between two parallel plates each of area 35.0cm and separated by 2.45mm of air. what charge must be on each plate?
5. (p.524 Prob.46) A parallel-plate capacitor has fixed charges +Q and -Q. The separation of the plates is then doubled. By what factor does the energy stored in the electric field change?