{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

# HW21Sol - Platt David Homework 21 Due 4:00 am Inst Ken Shih...

This preview shows pages 1–2. Sign up to view the full content.

Platt, David – Homework 21 – Due: Oct 28 2005, 4:00 am – Inst: Ken Shih 1 This print-out should have 8 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering. The due time is Central time. 001 (part 1 of 2) 10 points Given: B = b t , where b = 0 . 9 T / s (lower figure). Consider a changing magnetic field (from B 0 to B , upper figure) within a circle of radius 4 m. The magnetic field is pointing into the page and its magnitude is increasing. 4 m B 0 B 0 B 0 4 m B B B ~ t ~ B 0 B 0 B Find the direction of the induced emf E ind . 1. clockwise 2. counter-clockwise correct 3. out of the page 4. into the page Explanation: Let : a = 4 m and b = 0 . 9 T / s . Faraday’s Law of Induction: E ind = I ~ E ind · d~s = - d Φ B dt Lenz’s Law – Induced emf’s always oppose magnetic flux changes. Use a “bracket”, “[ ]”, to denote the direc- tions. The direction content of Faraday’s Law then reads, [ E ind ] = - d Φ dt = -⊗ = fl . The right hand rule then implies that the direction of E ind is counter-clockwise. This is consistent with Lenz’s Law: the magnetic field is increasing into the page, so the induced emf E ind creates a magnetic field out of the page to counter this change. 002 (part 2 of 2) 10 points Find the magnitude of the induced electric field E ind on the perimeter of the circular magnetic field.

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

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### Page1 / 4

HW21Sol - Platt David Homework 21 Due 4:00 am Inst Ken Shih...

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

View Full Document
Ask a homework question - tutors are online