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Unformatted text preview: roofner (bar784) – 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 . 4882 × 10 14 have been transferred, the potential difference between the conductors is 12 . 3 V. The charge on an electron is 1 . 60218 × 10 − 19 C . What is the capacitance of the system? Correct answer: 3 . 24109 × 10 − 6 F. Explanation: Let : e = 1 . 60218 × 10 − 19 C , N = 2 . 4882 × 10 14 electrons , and V = 12 . 3 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 . 4882 × 10 14 ) ( 1 . 60218 × 10 − 19 C) 12 . 3 V = 3 . 24109 × 10 − 6 F . 002 10.0 points A spherical capacitor consists of a conducting ball of radius 7 cm that is centered inside a grounded conducting spherical shell of inner radius 10 cm. What charge is required to achieve a potential of 1098 V on the ball of ra dius 7 cm? The Coulomb constant is 8 . 98755 × 10 9 N · m 2 / C 2 . Correct answer: 2 . 85061 × 10 − 8 C. Explanation: Let : k e = 8 . 98755 × 10 9 N · m 2 / C 2 , a = 7 cm = 0 . 07 m , b = 10 cm = 0 . 1 m and V = 1098 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 . 07 m) (0 . 1 m) (1098 V) (0 . 1 m) (0 . 07 m) = 2 . 85061 × 10 − 8 C . keywords: 003 (part 1 of 2) 10.0 points A 69 m length of coaxial cable has a solid cylindrical wire inner conductor with a di ameter of 2 . 666 mm and carries a charge of 8 . 49 μ C. The surrounding conductor is a cylindrical shell and has an inner diameter of...
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 Fall '00
 Littler
 Charge, Magnetism, Work, Correct Answer, Electric charge, CBC

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