Ch21-h2-solutions - pan (zp695) Ch21-h2 chiu (56565) 1 This...

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

View Full Document Right Arrow Icon

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

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: pan (zp695) Ch21-h2 chiu (56565) 1 This print-out should have 29 questions. Multiple-choice questions may continue on the next column or page find all choices before answering. 001 (part 1 of 2) 10.0 points A current-carrying wire is oriented along the y axis. It passes through a region 0 . 4 m long in which there is a magnetic field of 4 . 1 T in the + z direction. The wire experiences a force of 15 . 5 N in the- x direction. What is the magnitude of the conventional current in the wire? Correct answer: 9 . 45122 A. Explanation: We can find the current as follows: | F | = I L B = I L B I = F L B = 15 . 5 N (0 . 4 m)(4 . 1 T) = 9 . 45122 A . 002 (part 2 of 2) 10.0 points What is the direction of the conventional cur- rent in the wire? 1.- 1 , , 2. , , 1 3. 1 , , 4. , 1 , 5. ,- 1 , correct 6. , ,- 1 Explanation: Use the right-hand rule. The current flows in the- y direction. 003 (part 1 of 3) 10.0 points A metal rod of length 12 cm and mass 65 g has metal loops at both ends, which go around two metal poles as in the following figure. 12 cm 4 cm I = 4 A I = 4 A 70 gram rod I = 4 A The rod is in good electrical contact with the poles but can slide freely up and down. The metal poles are connected by wires to a battery, and a 4 A current flows through the region of the rod. An external magnetic field B is present in the region, large enough that you can neglect the magnetic fields due to the 4 A current. The magnetic field is oriented so as to have the maximum e ff ect on the rod. The rod sits at rest 4 cm above the table. Take the + x axis to be toward the right, the + y axis to be upward, and the + z axis out of the plane of the page. What is the (external) magnetic field in the region of the rod? Begin by finding the x component, B x . If necessary, use g = 9 . 8 m / s 2 . Correct answer: 0 T. Explanation: The metal rod is in equilibrium, so F net = 0. The gravitational force by Earth on the rod is downward, so the magnetic force by the magnetic field on the rod must be upward. Since F mag = I L B and I flows in the + x direction, B must be in the- z direction. Therefore we can immediately tell that the x and y components of the magnetic field are zero. 004 (part 2 of 3) 10.0 points Find B y . Correct answer: 0 T. Explanation: See the explanation for part 1. pan (zp695) Ch21-h2 chiu (56565) 2 005 (part 3 of 3) 10.0 points Find B z . Correct answer: 1 . 32708 T. Explanation: Based on what we discussed in part 1, we can apply the Momentum Principle to find F net = 0 F mag + F grav = 0 F mag = F grav I L B = m g B = m g I L = (65 g)(9 . 8 m / s 2 ) (4 A)(12 cm) = 1 . 32708 T . 006 (part 1 of 9) 10.0 points An electron travels with velocity 5 10 5 , , m / s ....
View Full Document

This note was uploaded on 02/21/2012 for the course PHY 303K taught by Professor Turner during the Spring '08 term at University of Texas at Austin.

Page1 / 8

Ch21-h2-solutions - pan (zp695) Ch21-h2 chiu (56565) 1 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