HW 12 - yang (ey942) – ohw 12 – turner – (56705) This...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
yang (ey942) – ohw 12 – turner – (56705) 1 This print-out should have 17 questions. Multiple-choice questions may continue on the next column or page – fnd all choices beFore answering. 001 (part 1 of 3) 10.0 points A total charge oF 11 mC passes through a cross-sectional area oF a nichrome wire in 3 . 6 s. a) What is the current in the wire? Correct answer: 0 . 00305556 A. Explanation: Let : Δ Q 1 = 11 mC and Δ t 1 = 3 . 6 s . I = Δ Q Δ t = 0 . 011 C 3 . 6 s = 0 . 00305556 A . 002 (part 2 of 3) 10.0 points b) How many electrons pass through the cross-sectional area in 6.50 s? Correct answer: 1 . 24132 × 10 17 . Explanation: Let : q e = 1 . 6 × 10 19 C and Δ t 2 = 6 . 50 s . Δ Q = N q e N = Δ Q q e = I Δ t 2 q e = (0 . 00305556 A)(6 . 5 s) 1 . 6 × 10 19 C = 1 . 24132 × 10 17 . 003 (part 3 of 3) 10.0 points c) IF the number oF charges that pass through the cross-sectional area during the given time interval doubles, what is the resulting cur- rent? Correct answer: 0 . 00611111 A. Explanation: Let : Δ Q 2 = 2 Δ Q 1 . I = 2 Δ Q 1 Δ t 1 = 2 (0 . 011 C) 3 . 6 s = 0 . 00611111 A . 004 10.0 points An electrician fnds that a 0 . 6 m length oF a certain type oF wire has a resistance oF 0 . 12 Ω. What is the total resistance oF the 115 m oF this wire he plans to use to wire a house? Correct answer: 23 Ω. Explanation: Let : 1 = 0 . 6 m , 2 = 115 m , and R = 0 . 12 Ω . A 0 . 6 m length oF the wire has a resistance oF λ = R 1 , so the total resistance oF the wire is R tot = λ ℓ = R 1 = p 0 . 12 Ω 0 . 6 m P (115 m) = 23 Ω . 005 (part 1 of 2) 10.0 points Suppose that a uniForm wire oF resistance R is stretched uniFormly to N times its original length. Assume the total volume oF the wire re- mains the same, and the volume is given by the product oF the cross sectional area and the length. Denote the original area by A and the area aFter the stretch by A .
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
yang (ey942) – ohw 12 – turner – (56705) 2 The ratio A A is 1. A A = 1 2. A A = 1 N 2 3. A A = N 2 4. A A = 1 N 2 / 3 5. A A = 0 6. A A = N 7. A A = N 8. A
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 11/21/2010 for the course PHY 56705 taught by Professor Turner during the Spring '10 term at University of Texas at Austin.

Page1 / 6

HW 12 - yang (ey942) – ohw 12 – turner – (56705) This...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online