This preview shows pages 1–3. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: nguyen (akn452) Homework #5 yu (44003) 1 This printout should have 20 questions. Multiplechoice questions may continue on the next column or page find all choices before answering. 001 10.0 points A capacitor network is shown in the following figure. 12 V 5 . 28 F 6 . 8 F 10 . 2 F a b What is the voltage across the 6 . 8 F upper righthand capacitor? Correct answer: 5 . 24503 V. Explanation: Let : C 1 = 5 . 28 F , C 2 = 6 . 8 F , C 3 = 10 . 2 F , and V = 12 V . Since C 1 and C 2 are in series they carry the same charge C 1 V 1 = C 2 V 2 , and their voltages add up to V , voltage of the battery V 1 + V 2 = V C 2 V 2 C 1 + V 2 = V C 2 V 2 + C 1 V 2 = V C 1 V 2 = V C 1 C 1 + C 2 = (12 V)(5 . 28 F) 5 . 28 F + 6 . 8 F = 5 . 24503 V . 002 (part 1 of 2) 10.0 points A 54 m length of coaxial cable has a solid cylindrical wire inner conductor with a di ameter of 2 . 59 mm and carries a charge of 10 . 47 C. The surrounding conductor is a cylindrical shell and has an inner diameter of 8 . 36 mm and a charge of 10 . 47 C. Assume the region between the conductors is air. The Coulomb constant is 8 . 98755 10 9 N m 2 / C 2 . What is the capacitance of this cable? Correct answer: 2 . 56371 nF. Explanation: Let : k e = 8 . 98755 10 9 N m 2 / C 2 , Q = 10 . 47 C , = 54 m , a = 2 . 59 mm , and b = 8 . 36 mm . The charge per unit length is Q . V = integraldisplay b a vector E dvectors = 2 k e integraldisplay b a dr r = 2 k e Q ln parenleftbigg b a parenrightbigg . The capacitance of a cylindrical capacitor is given by C Q V = 2 k e 1 ln parenleftbigg b a parenrightbigg = 54 m 2 (8 . 98755 10 9 N m 2 / C 2 ) 1 ln parenleftbigg 8 . 36 mm 2 . 59 mm parenrightbigg parenleftbigg 1 10 9 nF 1 F parenrightbigg = 2 . 56371 nF 003 (part 2 of 2) 10.0 points nguyen (akn452) Homework #5 yu (44003) 2 What is the potential difference between the two conductors? Correct answer: 4 . 08393 kV. Explanation: Therefore V = Q C = 10 . 47 C 2 . 56371 nF parenleftbigg 1 10 9 nF 1 F parenrightbigg parenleftbigg 1 C 1 10 6 C parenrightbiggparenleftbigg 1 kV 1000 V parenrightbigg = 4 . 08393 kV 004 10.0 points The electron volt is a measure of 1. velocity. 2. impulse. 3. momentum. 4. charge. 5. energy. correct Explanation: Electron volt (eV) is a unit commonly used in atomic and nuclear physics. It is defined as the energy that an electron gains or loses by moving through a potential of 1 V....
View Full
Document
 Spring '10
 Jarafee
 Physics, Work

Click to edit the document details