Electrostatics Review Package

Name: Electrostatics Review Package 1. Which diagram shows the electric field near a negative point charge? 2. Which pair of values will cause the greatest deflection of an electron beam in a cathode ray tube? 3. The magnitude of the net electric field at P in the diagram below is 5.0 x 103 N/C. Find the magnitude of charge Q2. 4. a) Find the electric potential at point A and at point B. (Note:1.0 μC is 1.0x10-6 C) b) What is the potential difference between A and B? c) 0.036 J of work must be done to move a charge q from A to B. Find the magnitude and polarity of this charge. 5. The diagram shows the electric field lines near two point charges, L and R. identify the polarity of these point charges. 6. An electron orbits the nucleus which carriers a charge of +9.6x10-19 C. If the electron’s orbital radius is 2.0x10-10 m, what is its potential energy? 7. Two charges are positioned as shown in the diagram below. a) Find the magnitude and direction of the electric field at A. (Note: 1.0 μC is 1.0x106 C) b) A charge placed at A experiences a force of 4.0x10-3 N towards the right. What are the magnitude and polarity of this charge? 8. In a cathode ray tube, 9. Charge Q1 is located 5.0 m from charge Q2 as shown How much work must be done to move charge Q1 2.0 m closer to charge Q2. 10. An electron passing between parallel plates 0.025 m apart experiences an upward electrostatic force of 5.1x10-16 N. a) What is the magnitude of the electric field between the plates? b) What is the potential difference between the plates? c) On the diagram below draw in the connections to the power supply necessary for the electron to experience this upward force. 11. Which of the following diagrams shows the electric field between two equal but opposite charges? 12. A proton initially at rest is accelerated between parallel plates through a potential difference of 700 V. What is the maximum speed reached by the proton? 13. What are the magnitudes of the electric field and the electric potential at point P midway between the two fixed charges? 14. A charge q of 30.0 μC is moved from point X to point Y. How much work is done on the 30.0 μC charge? (Note: 1.0 μC is 1.0x106 C) 15. An electron in the electric field has an electric force acting on it in what direction? 16. What is the potential at point P due to the two fixed charges as shown? 17. A moving proton has 6.4x10-16 J of kinetic energy. The proton is accelerated by a potential difference of 5 000 V between parallel plates. The proton emerges from the parallel plates with what speed? 18. a) How much work is done in moving an electron from point X to point Y? b) What is the potential difference between point X and point Y? 19. The electric field is uniform between 20. What is the magnitude and direction of the electric field at point P due to the two fixed charges? 21. A proton with kinetic energy of 2.1x10-17 J is moving into a region of charged parallel plates. The proton will be stopped momentarily in what region? 22. A proton, initially at rest at point X, will have what speed at point Y? 23. Which of the following best describes how electric potential varies with distance in the region around a point charge? 24. Three identical positive electric charges are fixed as shown in the diagram below. What is the direction of the net electric force on Q2 due to Q1 and Q3? 25. In an experiment, a positively charge oil droplet weighing 6.5x10-15 N is held stationary by a vertical electric field as shown in a diagram. If the electric field strength is 5.3x103 N/C, what is the charge on the oil droplet? Electrostatics Answers 1. D (Aug ’99, 18) 2. B (Aug ’99, 19) 3. 3.0x10-6 (Aug ’99, 20) 4. a) VA = -4.5x104V VB = -2.7x104V (Aug ’99, 5LA) b) 1.8x104V c) +2.0x10-6C 5. A (Jan. ’99, 18) 6. -6.9x10-18J (Jan ’99, 19) 7. a) E = 2.5x103N/C to the left (Jan ’99, 5LA) b) -1.6x10-6C 8. D (June ’99, 19) 9. 1.2x10-2 (June ’99, 20) 10. a) 3.2x103N/C (June ’99, 5LA) b) 80V c) + 11. A (Jan. ’00, 19) 12. 3.7x105m/s (Jan. ’00, 20) 13. C (Jan ’00, 21) 14. W = ΔE  EPy – EPx 3.9J (3.94J) (Jan ’00, 5LA) 15. West (June ’00, 18) 16. 7.1x103V (June ’00, 19) 17. 1.3x106m/s (June ’00, 20) 18. a) 2.4x10-15J (June ’00, 5LA) b) 1.5x104V 19. D (Aug ’00, 18) 20. B (Aug ’00, 19) 21. L (Aug ’00, 20) 22. 2.0x106m/s (Aug. ’00, 5LA) 23. B (Jan’01, 20) 24. to the left (Jan ’01, 20) 25. 1.2x10-18C (Jan. ’01, 22) connections