hw 29 - nguyen (jmn727) homework 29 Turner (59070) 1 This...

Info iconThis preview shows pages 1–2. 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: nguyen (jmn727) homework 29 Turner (59070) 1 This print-out should have 10 questions. Multiple-choice questions may continue on the next column or page find all choices before answering. 001 10.0 points What current is required in the windings of a long solenoid that has 2750 turns uni- formly distributed over a length of 0 . 312 m in order to produce a magnetic field of magnitude 0 . 000113 T at the center of the solenoid? The permeability of free space is 4 10 7 T m / A . Correct answer: 10 . 2021 mA. Explanation: Let : N = 2750 , L = 0 . 312 m , B = 0 . 000113 T , and = 4 10 7 T m / A . The magnetic field inside a long solenoid is B = n I = parenleftbigg N L parenrightbigg I . Thus the required current is I = B L N = (0 . 000113 T) (0 . 312 m) (4 10 7 T m / A) (2750) 1000 mA 1 A = 10 . 2021 mA . 002 10.0 points A single piece of wire is bent into the shape of Texas, with a total area of 5 . 42 cm 2 . This Texas shaped loop is perpendicular to a mag- netic field which increases uniformly in mag- nitude from 0 . 812 T to 1 . 65 T in a time of 2 s. The wire has a total resistance of 3 . What is the current? Correct answer: 0 . 0756993 mA. Explanation: Basic Concepts: Faradays Law of Induc- tion: E =- d B dt The particular shape of the wire is unimpor- tant, only the area enclosed by the wire mat- ters. The magnetic flux through the loop is given by = B A . d dt = d dt ( B A ) = A d B dt = A B t = A B 2- B 1 t = (0 . 000542 m 2 )(0 . 419 T / s) = 0 . 000227098 V . From Faradays Law: E =- d dt =- . 000227098 V From Ohms Law: I = E R = . 000227098 V 3 = 0 . 0756993 mA 003 10.0 points A toroid having a rectangular cross section ( a = 1 . 11 cm by b = 4 . 06 cm) and inner radius 4 . 95 cm consists of N = 440 turns of wire that carries a current I = I sin t , with I = 42 A and a frequency f = 69 . 9 Hz. A loop that consists of N = 31 turns of wire links the toroid, as in the figure....
View Full Document

Page1 / 5

hw 29 - nguyen (jmn727) homework 29 Turner (59070) 1 This...

This preview shows document pages 1 - 2. Sign up to view the full document.

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