Physics 132 Quiz # 17

Transcription

1 Name (please (please pint) pint) Physics 132 Quiz # The The magnitude of of the the magnetic field field due due to to the the pesence of of a chaged body body A) A) vaies diectly with with the the speed of of the the body. ) ) vaies diectly with with the the chage caied by by the the body. C) C) vaies invesely with with the the squae of of the the distance between the the chaged body body and and the the field field point. D) D) depends on on the the magnetic popeties of of the the space between the the chaged body body and and the the field field point. E) E) is is descibed by by all all of of these What is is the the diection of of the the magnetic field field aound a wie wie caying a cuent pependiculaly into into this this page? A) A) The The field field is is paallel to to and and in in the the same same diection as as the the cuent flow. flow. ) ) It It is is paallel to to but but diected opposite to to the the cuent flow. flow. C) C) It It is is counteclockwise aound the the wie wie in in the the plane of of the the page. D) D) It It is is clockwise aound the the wie wie in in the the plane of of the the page. E) E) None of of these these is is coect.

2 LECTURE 19 Announcements Exam II on 8:00 am in 118 NHS Emphasis on Ch Review Session on Sunday? Concepts & Topics: DC Engine Hall effect of a moving chage iotsavat law

3 DEMO: Foce on wies in field Concept Test: Test: Once the the cuent is is tuned on on the the wie wie moves 1.) 1.) upwad 2.) 2.) downwad 3.) 3.) towads the the N pole pole 4.) 4.) towads the the S pole pole

4 Toque on wies in field: APPLICATIONS DEMO: simple DC electical engine + Phase I Concept Test: Test: The The fame otates 1.) 1.) clockwise in in I I and and evese in in II II 2.) 2.) counteclockwise in in I I and and ev. ev. II II 3.) 3.) clockwise in in both both I I and and II II 4.) 4.) counteclockwise in in both both I I and and II II Phase II II +

5 The Hall effect (discoveed by Edwin Hall in 1879 as a student!) hole conduction high e density electon conduction low e density V H Ew vw I nqva nqv(wt) V H I nqwt w nqt I R V I H H nqt

6 DEMO on DVD: The Hall effect Question: Tun the the sample aound: the the Hall voltage changes sign. Explain why. Concept test: The ectangula aluminum stip in in the the figue is is in in a unifom magnetic field,.the cuent I I is is flowing pependicula to to suface Positive chages will accumulate on on A) A) suface ) ) suface C) C) suface D) D) the the suface opposite suface E) E) none of of these sufaces.

7 SOURCES OF MAGNETIC FIELD cuents geneate magnetic field (see figue) The fundamental souce of magnetism: motion of chage µ 4π 0 qv ˆ 2 Concept Test:A positively chaged body body is is moving in in the the negative z diection as as shown. The The diection of of the the magnetic field field due due to to the the motion of of this this chaged body body at at point point P is is 1.) 1.) 1 2.) 2.) 2 3.) 3.) 3 4.) 4.) 4 5.) 5.) 5

8 The iotsavat Law What is is the equivalent of of Coulomb s law fo fo magnetic field ceated by by cuents? d µ 0 Idl ˆ 1 dq de ˆ 2 2 4π 4πε 0 iotsavat Law Examples µ 0 2π I R Coulomb s Law µ 0 2 I R distance R fom wie cente of a loop ni µ 0 cente of solenoid

9 Concept Test: Cuentcaying wies ae ae located along two two edges of of a cube with with the the diections of of the the cuents as as indicated. The The vecto that that indicates the the esultant magnetic field at at the the cone of of the the cube is is 1) 1) 1 2) 2) 2 3) 3) 3 4) 4) 4 5) 5) 5 Concept Test:A solenoid caies a cuent An An electon is is injected with velocity v along the the axis A of of the the solenoid. When the the electon is is at at C, C, it it expeiences a foce that is is 1) 1) zeo. 2) 2) not zeo and along A.. 3) 3) not zeo and along A. 4) 4) not zeo and pependicula to to the the page. 5) 5) None of of these is is coect.

10 Inteaction between cuent caying wies Concept Test: Two Two vey vey long, long, paallel conducting wies cay cay equal cuents in in opposite diections. The The numbeed diagams show end end views of of the the wies and and the the esultant foce foce vectos due due to to cuent flow flow in in each each wie. wie. Which diagam best best epesents the the diection of of the the foces? 1) 1) 1 2) 2) 2 3) 3) 3 4) 4) 4 5) 5) 5