Multiple choice 1. You can readily pick up small pieces of paper with a plastic comb or ruler. Which display ( ) as we call it today. Static electricity B. Force C. Electric field D. Electric current 2. What are the small particles called that make up matter? Electron B. Atom C. Proton D. Charges 3. Why are protons and electrons attracted to each other?  A. Protons have positive charge and electrons have a negative charge. B. Protons have a negative charge and electrons have a positive charge. C. Protons and electrons are both positively charged. D. Protons and electrons are both negatively charged 4. Why is it important that the electrons and protons are attracted to each other?  A. The attraction determines the size of the atom. B. The attraction keeps the electrons from flying away from the nucleus. C. The attraction determines the size of the nucleus. D. The attraction determines the charge of the atom. 5. The size of the electric force depends upon which two things?  A. The amount of each charge and the size of the electric field. B. The distance between the charges and the size of the electric field. C. The number of protons and the distance between the charges. D. The amount of each charge and the distance between the charges. 6. What method is involved when charges in an uncharged metal object are rearranged without direct contact with the charged object?  A. Friction B. Induction C. Convection D. Conduction 7. Which of the following is positively charged?  A. Proton B. Neutron C. Electron D. Atom 8. Which of the following is NOT an insulator?  A. Air B. Wood C. Glass D. Cooper 9. The method of charging happens when you rub a balloon on your hair is:  A. Friction B. Resistance C. Electric Force D. Static Electricity 10. The force between two objects is called:  A. Electrical conductor B. Voltage C. Electric Force D. Electric Field 11. Which of the following are true of static charges? A. Like charges repel B. Like charges attract. C. Opposite charges repel. D. Opposite charges attract. 12. Which of the following are true of static charges? A. A positively charged object has lost electrons. B. A positively charged object has gained protons. C. A negatively charged object has lost protons. D. A negatively charged object has gained electrons. 13. Electric current originates from which part of an atom? A. Nucleus B. Positively charged protons C. Negatively charged electrons D. Entire atom acting as a unit 14. Which of the following is true of electrical forces? A. Electrical forces are produced by electrical charges. B. Like charges attract, unlike charges repel. C. Electrical forces are weaker than gravitational forces. D. Positive and negative charges can combine to produce a third type of charge. 15. How can electric charge be established? A. Electrons can be removed from atoms and accumulated to produce a negative charge B. Atoms from which electrons have been removed produce positive electric charge. C. Both A and B. D. Neither A nor B. 16. When a person combs her hair, static electricity is sometimes generated by what process? A. Contact between the comb and hair results in a charge. B. Friction between the comb and hair transfers electrons. C. Deduction between the comb and hair. D. Induction between the comb and hair. 17. Which of the following is not an electrical classification of materials? A. Conductors, which have electrons that move freely. B. Insulators, whose electrons essentially do not move between atoms. C. Semi-insulators, which sometimes conduct and sometimes insulate. D. Semiconductors, which sometimes conduct and sometimes insulate. 18. Coulomb's law relates charge and distance between interacting charged bodies, describing the electrical force as being A. Proportional to the sum of the charge. B. Inversely proportional to the distance between charges. C. Proportional to the product of the charges and inversely proportional to the distance. D. Proportional to the product of the charges and inversely proportional to the distance squared. 19. Electrical as well as gravitational effects can be thought to be caused by fields. Which of the following is true of an electrical or gravitational field? A. The field concept is often used to describe contact forces. B. A gravitational or electrical field does not always exist in the space around an object. C. Fields are useful for understanding forces acting through a distance. D. There is no way to verify the existence of a force field since it is just a concept. 20. Electrical voltage is a measure of A. total amount of current. B. how much current is moving through a circuit. C. the ratio of work done moving electric charges. D. how many electrons are moving through a wire. 21. Value of k in coulomb's law depends upon A. magnitude of charges B. distance between charges C. both A and B D. medium between two charges 22. Force between two bodies having charges 500μC and 100μC separated by distance of 0.5m in air is A. 1800N B. 1000N C. 2200N D. 300N 23. In coulomb's law force of attraction or repulsion between two charges is A. inversely proportional to charges B. directly proportional to product of charges C. directly proportional to square of distance between them D. Inversely proportional to distance between them 24. Law stating that "force is directly proportional to product of charges and inversely proportional to square of separation between them" is called A. newton's law B. coulombs law C. gauss's law D. Ohm's law 25. Two positive charges Q1 = 16 C and Q2 = 4 C, separated by a diameter of 3 m will produce force of A. 40 N B. 41.1 N C. 42.3 N D. 42.7 N 26. Formula that describes statement of Coulomb's law is A. F = kQ1Q2/r² B. F = Q1Q2/r² C. F = kQ/r² D. F = kQ1Q2/r 27. Value of constant K in Coulomb's law has value of A. 9 × 10³ B. 9 × 105 C. 9 × 107 D. 9 × 109 28. Electric charges under action of electric forces is called A. electrostatic B. electric flux C. electric field D. electric field lines 29. If we have a positive and a negative charge, then force between them is A. positive B. negative C. zero D. infinite 30. Electrical force exerted by two point charges on each other is inversely proportional to A. sum of their charges B. product of their charges C. distance between them D. square of distance between them 31. Particles involved in movement within material are A. protons B. electrons C. neutrons D. positrons 32. Phenomena in which a charged body attract uncharged body is called A. electrostatic induction B. electric current C. charge movement D. magnetic induction 33. An uncharged object has A. more protons B. more electrons C. equal electrons and protons D. no protons and electrons 34. Fields that act on objects with masses are A. electric fields B. magnetic fields C. force fields D. gravitational fields 35. Where an electric charge experiences a force, there is an A. electric field B. magnetic field C. electric current D. conventional current 36. Region around a charge q in which it exerts force on a test charge is called A. electric field intensity B. electric force C. electric field D. coulomb's force 37. Field lines always emerge from A. negative charge B. positive charge C. can be both charges D. the central point of both charges 38. Direction of free test charge will be A. direction of electric intensity B. direction of coulomb's force C. direction of magnetic intensity D. direction of protons 39. Spacing between field lines shows A. their direction B. their position C. both A and B D. their strength 40. Electric field intensity is A. a base quantity B. a scaler quantity C. A and B both D. a vector quantity II. Calculation Determine the magll1tude and direction of the electric force on the electron of a hydrogen atom exerted by the single proton (Q2 = +e) that is the atom's nucleus. Assume the average distance between the revolving electron and the proton is r = 0.53 X 10-10 m (hint: Q1 = Q2 = 1.6 X 10-19C, F = Q1 Q2/r2) Three charged particles are arranged in a line, as shown in Fig. Calculate the net electrostatic force on particle 3 (the -4.0μC on the right) due to the other two charges (hint: F = Q1 Q2/r2, F = F1 + F2) Calculate the magnitude and direction of the electric field at a point P which is 30 cm to the right of a point charge Q = -3.0 X 10-6 C Draw the electric field line for the positive charge Draw the electric field line for the negative charge