Name period 3 rd 9 weeks test PEOPLE and SYMBOLS practice Instructions: Work in groups following Quiz-Quiz-Trade activity Date: Monday 2/25/13 Write what each symbol means, including the unit Symbol Meaning unit 1. F electric 2. k 3. q 4. r 5. E 6. R Total 7. 1/R Total 8. P 9. V 10. I 11. R 12. Q 13. N 14. e 15. F magnetic 16. v 17. B 18. l
Write the name of the person who contributed the idea/concept/ theory 19. Whose law for electric charges relates type, size, and distance between the charges to the force on each charge? 20. Who is the scientist that created an experiment using oil drops placed within a capacitor field to show that all charges are a multiple of 1.6 x 10 19 Coulomb? (ex. Electron and proton charges) 21. Which of the following scientists supported the idea of two kinds of charge and invented lightning rods? 22. Who determined the planetary model of an atom that has electrons orbiting around a heavy, positively charged nucleus. 23. Developed 4 equations describing electromagnetism, including the speed of light 24. electromagnetic induction that an electric current created a magnetic field, and that a moving magnetic source could induce a current. 25. formulated the law of magnetic induction quantitatively 26. Measured the speed of light (c= 3.0x10 8 m/s) 27. predicted that light and other waves (radar, X-rays, etc.) are electromagnetic waves, and he also described their properties. 28. the speed of light is the same regardless of your own motion; result is the heart of Einstein s Special Theory of Relativity 29. Changing electric fields (new concept in these equations) induce changing magnetic fields 30. Developed the theory of induction 31. Motors, generators, and transformers
Name period 3 rd 9 weeks test CALCULATION practice Part 1: IWB Instructions: Show all formulas and work in the space provided. Complete IWB activity using questions below. Fill-in with numbers from IWB and solve. Show your answer on the marker board provided. Date: Tuesday 2/26/13 Formulas F electric = k(q 1 q 2) /r 2 E=Fq R Total = R 1 + R 2 + R 3 1/R Total = 1/R 1 + 1/R 2 + 1/R 3 P=VI I=V/R Q=Ne F magnetic =qvb F magnetic = BIl Constants and conversions 1m= 100cm 1m= 1000mm Charge on electron= -1.6x10-19 C Charge on Proton= +1.6x10-19 C k c = Coulomb s constant= 8.99x10 9 N m 2 /C 2 1. Two charged spheres are 20 cm apart and exert an attractive force of 8 x 10 9 N on each other. What will be the force of attraction when the spheres are moved to 10 cm apart? 2. A positive 6.0 x 10-9 C charge experiences a force of 1.8 x 10-5 N to the right. What is the electric field at the location of that charge from other charges? 3. A piece of fur is rubbed against a plastic rod. The resulting charge on the rod is -18 microcoulombs. What charge does the fur acquire?
4. How much charge (Q) could a capacitor hold if it has 4.5 billion (4.5x10 9 ) elementary charges (electrons)? 5. A 9.0 volt battery is connected in a series to four identical 4.00 ohm resistors connected in parallel to each other. What are the current and power through the circuit? 6. A 0.25 C positive charge moves to the south at a speed of 250 m/s and enters a region of uniform magnetic field. It experiences a force of 20 N down. What is the magnetic field? 7. A straight current-carrying wire is in a uniform magnetic field oriented at right angles to the wire. If 1.14m of wire is in the 0.72-T field, and the force on the wire is 0.33 N, what is the current in the wire?
Name period 3 rd 9 weeks test CALCULATION practice Part 2: in class practice Instructions: Show all formulas and work on a separate sheet and staple to this handout. Show answers with units in the space provided, No work on separate sheet = no credit. Date: Wednesday 2/27/13 Finish for homework if needed 1. Two identical insulated metal spheres are separated by 10.0 cm. Equal charges are placed on each sphere, which results in a force of 2.3 x 10 14 N. Each charge is tripled in size, and the distance between the spheres is increased to 20.0 cm. What is the magnitude of the force on the sphere after the changes have been made? 2. A particle of ink in an ink-jet printer carries a charge of -8 x10-13 C and is deflected onto paper with a force of 3.2 x10-4 N. Find the strength of the electric field 3. A piece of fur is rubbed against a plastic rod. The resulting charge on the fur is +24 microcoulombs. What charge does the rod acquire? 4. How many electrons would need to be removed from an object to produce a charge of 8.00 microcoulombs? (1 microcoulomb = 1 x 10-6 Coulombs) 5. A 420 ohm resistor draws 0.52 A of current. What is the power dissipated by this resistor in watts? 6. An electron travels at a uniform speed of 3.0 x 10 6 m/s to the east. If then enters a uniform magnetic field and experiences a maximum force of 5.0 x 10-19 N. What is the magnetic field?
8Ω 7Ω 10Ω 9V 5Ω 7. Use the diagram above to answer the following questions a. Find the total resistance of the circuit shown above. b. What is the amount of current flowing through the system? c. What is the potential difference across the 10 ohm resistor? 8. A beam of protons travels at 3.5 10 6 m/s through a uniform magnetic field of 5.7 10-2 T. The beam of electrons is perpendicular to the field. How strong is the force acting on each proton? 9. An electron moving at 5.6 10 7 m/s travels through a uniform magnetic field of 1.4 T at right angles to the field. How strong is the force that acts on the electron? 10. A 10-m long wire carrying 5 A of current is at right angles to a uniform magnetic field of 0.01 T. What is the magnitude of the force on the wire? 11. A straight wire that carries a 4.6-A current is in a uniform magnetic field oriented at right angles to the wire. The magnetic field has a strength of 1.2 T. If the force exerted on the wire is 0.60 N, what length of wire is in the magnetic field?
Name period 3 rd 9 weeks test STATIONS practice Instructions: Thursday= rotate in groups to different stations, answering the questions as a group and taking notes. Friday= answer questions below based on group station activities on Thursday DUE: Monday 3/4/13 Open-ended Questions: write your answers in the space provided 1. What process is being described? A charged rod is brought close to, but does not touch, an uncharged sphere, while a third object touches and is then removed from the sphere, leaving behind an unbalanced charge 2. According to Coulomb's Law, which should the student do to increase the electrical force of repulsion between these balloons? 3. What is the function of an electroscope? Explain how is works. 4. A capacitor is a device that can store electric charges. In a common design, charge is conducted to non-touching parallel plates where it is stored for use later. In order to move a charge in and out of the capacitor plates, what type of material must be between the two plates? 5. In the water flow analogy, the current in a circuit is analogous to and resistors in a circuit are analogous to. 6. What is generally the most dangerous aspect of electricity: the voltage or current? Why? 7. One light bulb in the kitchen burns out and suddenly several lights go out in the house. This would provide evidence that the bulbs were wired in what kind of circuit?
8. Explain the difference between a conductor and provide 2-3 examples of each. Look at the formulas I=V/ R and P=VI 9. What happens to power when: a. Current increases? b. Voltage increases? c. Resistance increases? Using a 6V battery and 3 resistors: 10. Draw a series circuit and explain what it means for circuit elements to be in series with each other". 11. Draw a parallel circuit and explain what it means for circuit elements to be in parallel with each other". 12. Which type of circuit shares the current? 13. Which type of circuit would decrease the total current, I, flowing through this circuit?
True or False Questions: write the answer in the blank provided 14. True or false: In order to avoid being shocked when working with live circuits, you should only touch bare wires. 15. Voltmeters are used to measure the potential difference across circuit components such as resistors. Voltmeters have high resistance and are placed in parallel with the resistor. 16. Most good insulators of electricity are also good conductors of heat. 17. In order to make a stronger electromagnet, you must use more turns (wraps) of wire, use an iron core instead of a wooden, and use more current through the wire. Use the picture below for the true/ false statements in questions 18-21. 18. The iron in the nail makes the magnet stronger. 19. The head of the nail is always the S pole regardless of how the battery is hooked up or the wires are wound. 20. The point of the nail is the N pole of this electromagnet. 21. Electromagnets are magnetic dipoles. Multiple Choice 22. In which situation will a charged particle experience a force from interacting with magnetic fields? a. a charged particle moving parallel to magnetic field lines b. a charged particle moving perpendicular to magnetic field lines c. all of the above d. none of the above
23. A long, straight wire carries an electrical current. Which is the BEST description regarding the magnetic field created by the current? a. A straight wire does not create magnetic fields. b. It is weak but parallel to the wire, in the direction of the current. c. It circles the wire forming a loop. d. It spirals around the wire like a slinky, with the current in the center. 24. Which pole of the magnet is the North pole, and in which direction does the magnetic field point between the poles? a. Left pole is N, magnetic field points to the right. b. Left pole is N, magnetic field points to the left. c. Right pole is N, magnetic field points to the right. d. Right pole is N, magnetic field points to the left.