Review for Statics and Magnetism Test

Transcription

1 Review for tatics and Magnetism Test Multiple Choice 1. The following diagram represents some of the magnetic lines of force between two bar magnets. Pole X of one magnet and pole Y of the other magnet were brought close together. X Y Which of the following statements is true? A) X and Y are south poles. C) X is a south pole, and Y is a north pole. B) X and Y are north poles. D) X is a north pole, and Y is a south pole. 2. The following diagram shows two bar magnets and two compasses placed in a certain way. Compass Compass Magnet 1 Magnet 2 The poles are not indicated on magnets 1 and 2 in the diagram, but the compass needles show the direction of the magnetic fields of these magnets. Which of the following diagrams correctly indicates the poles of these magnets? A) Magnet 1 Magnet 2 B) Magnet 1 Magnet 2 C) Magnet 1 Magnet 2 D) Magnet 1 Magnet 2

2 3. You are given four electrically charged spheres. You know that sphere 1 is negatively charged. The following diagrams show what happens when these spheres are suspended in pairs close to each other. Which of the following diagrams correctly indicates the charge on spheres 3 and 4 and shows what will happen to them when they are suspended close to each other? 4. In the laboratory, you are given an ebonite rod, a piece of cotton and the following electrostatic list. Capacity to Ebonite gain electrons Polyethylene Glass The following diagram shows the ebonite rod and the piece of cotton before they are rubbed together. Ebonite rod Which of the following diagrams correctly shows the transfer of electric charges after the ebonite rod and the piece of cotton were rubbed together? Ebonite A) C) Ebonite B) Ebonite D) Ebonite

3 5. The following diagram shows a bar magnet and four compasses. Which compass shows the needle pointing in the correct direction? A) Compass 1 B) Compass 2 C) Compass 3 D) Compass 4 6. After being rubbed on hair, a rubber balloon acquires an electrical charge. When a piece of positively charges cotton is brought close to the balloon, the two objects will attract each other. What will happen to this balloon if it is brought close to a negatively charged plastic rod and why? A) The balloon will be repelled because it is positively charged. B) The balloon will be repelled because it is negatively charged. C) The balloon will be attracted because it is positively charged. D) The balloon will be neither attracted nor repelled because it is neutral 7. Five metallic spheres were electrically charged and then suspended as shown in the diagram below: If sphere A is positively charged, which of the spheres are negatively charged? A) B and C B) C and D C) D and E D) B and E 8. Tom wants to prepare a surprise party for his baby sister. Amongst other things, he wants to decorate the walls of their house with multi-coloured balloons. Once the balloons are inflated, Tom rubs them on his hair for a few seconds and then sticks them to the wall. He knows that this is possible due to friction, as the balloons become electrically charged and are attracted to the wall. Which of the following produced the static electricity? A) The transfer of protons between the hair and the balloons. B) The transfer of electrons between the hair and the balloons. C) The transfer of electrons between the balloons and the wall. D) The transfer of protons between the balloons and the wall.

4 9. Which of the statements below is TRUE? A) Positively charged objects have fewer protons than electrons. B) Positively charged objects have more electrons than protons. C) egatively charged objects have more electrons than protons. D) egatively charged objects have more protons than electrons. hort Answer 10. Demonstrations using ebonite rods and wool cloth are very common in static electricity activities. After being rubbed with wool, an ebonite rod attracts small objects. Ebonite is known to hold its electrons very tightly when rubbed against other substances. Wool on the other hand, exerts very weak attraction on its electrons. The diagram below shows the distribution of electrical charges before the two objects (ebonite rod and wool) are rubbed together: a- how the distribution of electrical charges in the two substances after the two objects are rubbed together (use and -). Explain your diagram. b- Explain why the ebonite rod attracts small objects after being rubbed with the wool cloth. 11. During a static electricity lab, a student rubs 5 pieces of different materials together two at a time. Table 1 below shows which of two materials were rubbed and which became negatively charged once they were rubbed. Table 1- egatively charged materials Materials being rubbed ubstance which gained electrons Wood and nickel ickel Wood and silk Wood Wood and lead Wood Lead and nickel ickel Lead and silk ilk ickel and silk ickel ickel and glass ickel Wood and glass Wood Glass and lead Lead Glass and silk ilk

5 Using the information in Table 1, you must put the 5 materials in order starting with the substance which will most easily gains electrons (becomes negatively charged) to the substance which will most easily lose electrons (becomes positively charged). Object 1. Tendency to attract electrons A student conducted an experiment involving three electrically charged spheres A, B and C. The steps in the experiment and some of the results are given below. /2 TEP REULT 1. Bring sphere A close to sphere B. 1. They repelled each other. 2. Bring sphere A close to sphere C. 2. They attracted each other. 3. Bring sphere B close to sphere C. 3.? Given the above information, what was the result of tep 3? 13. Put in the current direction on the diagram below. 14. Put in the compass direction.

6 15. Choose the diagrams which are correctly represented, 16. For the spheres below, determine which is positively charges, which is negatively charged and which is neutral.