This preview shows pages 1–2. 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: brown (twb493) – ch20h3 – chiu – (56565) 1 This printout should have 7 questions. Multiplechoice questions may continue on the next column or page – find all choices before answering. 001 10.0 points A 0 . 19 μ F capacitor is given a charge Q . After 1 s, the capacitor’s charge is 0 . 5 Q . What is the effective resistance across this capacitor? Correct answer: 7 . 59313 MΩ. Explanation: Let : C = 0 . 19 μ F = 1 . 9 × 10 7 F and t = 1 s . The charge on the capacitor is Q ( t ) = Q e t/τ . e t/τ = Q Q t τ = ln parenleftbigg Q Q parenrightbigg τ = t ln parenleftbigg Q Q parenrightbigg . The effective resistance is R = τ C = t C ln parenleftbigg Q Q parenrightbigg = 1 s (1 . 9 × 10 7 F) ln parenleftbigg Q . 5 Q parenrightbigg · 1 MΩ 10 6 Ω = 7 . 59313 MΩ . 002 (part 1 of 2) 10.0 points A 12 V automobile battery is connected to an electric starter motor. The current through the motor is 223 A....
View
Full
Document
This note was uploaded on 12/01/2011 for the course PHY 303L taught by Professor Turner during the Fall '08 term at University of Texas.
 Fall '08
 Turner
 Physics, Power

Click to edit the document details