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PHY 2049: A review 21. Coulomb’s law. 22. Electric fields, vector superposition. 23. Gauss’ law, E due to various charge distributions 24. Electric Potential, superposition 25. Capacitors 26. Current and Resistance 27. Circuits Tips • The exam will be held here during the usual class hours (12:30-2:00PM) on Monday June 6, 2011. • You are allowed a calculator, a #2 pencil and erasor and a single page formula sheet. The sheet must contain only formula. • Please bring your student ID. • Do not wear a hat in class during an exam. • Please do not use any electronic communication during the exam. • At this time, practice old exams. Question • Four identical light bulbs A, B, C and D are connected in series to a constant voltage source. A wire is then connected across B. What is the brightness of A relative to its former brightness? • (1) 0.44 (2) 0.56 none of these (3) 1.78 (4) 2.25 (5) • Two isolated conducting spheres are separated by a large distance. Sphere 1 has a radius of R and an initial charge 2Q while sphere 2 has a radius of 3R and an initial charge 8Q. A very thin copper wire is now connected to the spheres. Charge flows between the spheres until they reach the same electrical potential. How much charge will be transferred from sphere 2 to sphere 1? (Note that the charge transferred can be positive, negative or zero .) (1) Q/2 (2) 2Q (3) –Q/3 (4) -3Q (5) None of these A Formula sheet