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Unformatted text preview: Create assignment, 99552, Homework 18, Apr 01 at 8:48 pm 1 This printout should have 23 questions. Multiplechoice questions may continue on the next column or page find all choices before answering. The due time is Central time. Charge in a Nickel 23:01, trigonometry, numeric, > 1 min, nor mal. 001 We want to find how much charge is on the electrons in a nickel coin. Follow this method. A nickel coin has a mass of about 5 g. Each mole (6 . 02 10 23 atoms) has a mass of about 58 g. Find the number of atoms in a nickel coin. Correct answer: 5 . 18966 10 22 atoms. Explanation: Let : N a = 6 . 02 10 23 atoms , M = 58 g , and m = 5 g . Mass is proportional to the number of atoms in a substance, so for m grams in N atoms in the nickel coin and M grams in N a atoms in one mole, we have m M = N N a N = m M N a = (5 g) (58 g) (6 . 02 10 23 atoms) = 5 . 18966 10 22 atoms . 002 Find the number of electrons in the coin. Each nickel atom has 28 electrons / atom. Correct answer: 1 . 4531 10 24 electrons. Explanation: Let : n Ni = 28 electrons / atom . If n Ni electrons are in each Nickel atom, then the total number of electrons n e in the coin is n e = N n Ni = ( 5 . 18966 10 22 atoms ) (28 electrons / atom) = 1 . 4531 10 24 electrons . 003 Find the magnitude of the charge of all these electrons. Correct answer: 232813 C. Explanation: Let : q e = 1 . 60218 10 19 C / electron . The total charge q for the n e electrons is q = n e q e = (1 . 4531 10 24 electrons) ( 1 . 60218 10 19 C / electron ) = 232813 C , which has a magnitude of 232813 C . keywords: Charge in Lightning 03 23:01, trigonometry, numeric, > 1 min, nor mal. 004 A strong lightning bolt transfers about 25 C to Earth. The charge on an electron is 1 . 60218 10 19 C. How many electrons are transferred? Correct answer: 1 . 56038 10 20 . Explanation: Let : q = 25 C . The charge is proportional to the number of electrons, so q = nq e n = q q e = 25 C 1 . 60218 10 19 C = 1 . 56038 10 20 . Create assignment, 99552, Homework 18, Apr 01 at 8:48 pm 2 keywords: AP EM 1998 MC 39 40 23:05, trigonometry, numeric, > 1 min, wordingvariable. 005 Two charged particles of equal magnitude (+ Q and Q ) are fixed at opposite corners of a square that lies in a plane (see figure be low). A test charge q is placed at a third corner. + Q q Q What is the direction of the force on the test charge due to the two other charges? 1. correct 2. 3. 4. 5. 6. 7. 8. Explanation: The force between charges of the same sign is repulsive. The force between charges with opposite signs is attractive. + Q q Q The resultant force is the sum of the two vectors in the figure above. Therefore the correct choice is 006 If F is the magnitude of the force on the test charge due to only one of the other charges, what is the magnitude of the net force act ing on the test charge due to both of these charges?...
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 Spring '08
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 Physics, Charge, Work

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