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Unformatted text preview: lim (kl9356) – Homework 7 – Weathers – (22202) 1 This printout should have 10 questions. Multiplechoice questions may continue on the next column or page – find all choices before answering. 001 10.0 points Two conductors insulated from each other are charged by transferring electrons from one conductor to the other. After 2 . 274 × 10 14 have been transferred, the potential difference between the conductors is 15 . 7 V. The charge on an electron is 1 . 60218 × 10 − 19 C . What is the capacitance of the system? Correct answer: 2 . 3206 × 10 − 6 F. Explanation: Let : e = 1 . 60218 × 10 − 19 C , N = 2 . 274 × 10 14 electrons , and V = 15 . 7 V . One conductor gains a charge of Q = N e while the other gains a charge of Q. The capacitance of the system is C = q V = N e V = (2 . 274 × 10 14 ) ( 1 . 60218 × 10 − 19 C) 15 . 7 V = 2 . 3206 × 10 − 6 F . 002 10.0 points A spherical capacitor consists of a conducting ball of radius 15 cm that is centered inside a grounded conducting spherical shell of inner radius 17 cm. What charge is required to achieve a potential of 1452 V on the ball of ra dius 15 cm? The Coulomb constant is 8 . 98755 × 10 9 N · m 2 / C 2 . Correct answer: 2 . 05985 × 10 − 7 C. Explanation: Let : k e = 8 . 98755 × 10 9 N · m 2 / C 2 , a = 15 cm = 0 . 15 m , b = 17 cm = 0 . 17 m and V = 1452 V . The capacitance of a spherical capacitor is given by C = a b k e ( b a ) . The charge required to achieve a potential difference V between the shell and the ball is given by Q = C V = 1 k e a b V ( b a ) = 1 (8 . 98755 × 10 9 N · m 2 / C 2 ) × (0 . 15 m) (0 . 17 m) (1452 V) (0 . 17 m) (0 . 15 m) = 2 . 05985 × 10 − 7 C . keywords: 003 (part 1 of 2) 10.0 points A 22 m length of coaxial cable has a solid cylindrical wire inner conductor with a di ameter of 2 . 633 mm and carries a charge of 7 . 62 μ C. The surrounding conductor is a cylindrical shell and has an inner diameter of...
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This note was uploaded on 09/07/2010 for the course PHYS 2220 taught by Professor Littler during the Spring '00 term at North Texas.
 Spring '00
 Littler
 Charge, Magnetism, Work

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