Chapter 21 Review Questions

# Current xxxxx xxxxx xxxxx xxxxx xxxxx xxxxx 1

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Unformatted text preview: clockwise 1) 2) counterclockwise 3) no induced current ConcepTest 21.3b Moving Wire Loop II ConcepTest Moving A wire loop is being pulled wire through a uniform magnetic field that suddenly ends. field What is the direction of the 1) clockwise 1) 2) counterclockwise 3) no induced current induced current? xxxxx The B field into the page is disappearing in xxxxx the loop, so it must be compensated by an induced flux also into the page. This can induced xxxxx be accomplished by an induced current in xxxxx the clockwise direction in the wire loop. the direction xxxxx xxxxx Follow-up: What happens when the loop is completely x x of the field? x x out x ConcepTest 21.3c Moving Wire Loop III ConcepTest Moving What is the direction of the What induced current if the B field suddenly increases while the suddenly loop is in the region? xxx x xxx xxx x xxx xxx x xxx xxx xxx x xxx xxx x xx x 1) clockwise 1) 2) counterclockwise 3) no induced current xxxxxxxx xx xxxxxxxx xx xxxxxxxx xx xxxxxxxx xx xx xxxxxxxx xx xxxxxxxxxxx ConcepTest 21.3c Moving Wire Loop III ConcepTest Moving What is the direction of the What induced current if the B field suddenly increases while the suddenly loop is in the region? 1) clockwise 1) 2) counterclockwise 3) no induced current xxxxxxxxxxx x xxxxx must be countered by an induced xxxxxxxxxxx x flux out of the page. This can be flux xxxxx xxxxxxxxxxx accomplished by induced current x xxxxx in the counterclockwise direction in direction xxxxxxxxxxx xxxxx x in the wire loop. xxxxx xxxxxxxxxxx x xx x x Follow-up: What if the loop stops moving whilexthe field increases? The increasing B field into the page ConcepTest 21.4 Shrinking Wire Loop Shrinking If a coil is shrinking in a If 1) clockwise 1) magnetic field pointing into 2) counterclockwise the page, in what direction 3) no induced current is the induced current? ConcepTest 21.4 Shrinking Wire Loop Shrinking If a coil is shrinking in a If 1) clockwise magnetic field pointing into 2) counterclockwise the page, in what direction 3) no induced current is the induced current? The magnetic flux through the loop is decreasing, so the induced B field must decreasing try to reinforce it and therefore points in the same direction — into the page. into According to the right-hand rule, an induced clockwise current will generate clockwise a magnetic field into the page. into ConcepTest 21.8a Loop and Wire I ConcepTest Loop A wire loop is being pulled away from a current-carrying wire. What is the direction of the induced current in the loop? induced I 1) clockwise 2) counterclockwise 3) no induced current ConcepTest 21.8a Loop and Wire I ConcepTest Loop A wire loop is being pulled away wire from a current-carrying wire. What is the direction of the induced current in the loop? induced The magnetic flux is into the page on the into right side of the wire and decreasing due decreasing to the fact that the loop is being pulled away. By Lenz’s Law, the induced B field will oppose this decre...
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## This document was uploaded on 09/24/2013.

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