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Chrome File Edit View History Bookmarks People Window Help Morehead State University An Astronaut Who is Repa C ning.com, 2673390 Question 13 of 20 Map Sapling Learning macmillan learning A 45.0-cm wire is moving to the right at a speed of 7.30 m/s x across two parallel wire rails that are connected on the left T side, as shown in the figure. The whole apparatus is immersed in a uniform magnetic field which has a 0.890 T magnitude of 0.890 Tandis directed into the screen. What is the emf induced in the wire? 7.30 m/s 45.0 cm Number The induced emf causes a current to flow in the circuit formed by the moving wire and the rails. In what direction does the current flow around the circuit O counter-clockwise clockwise If the moving wire and the rails have a combined total resistance of 1.150, what applied force would be required to keep the wire moving at the given velocity? Assume that there is no friction between the moving wire and the rails. Number Previous Check Answer 0 Next Ex r Hint 16% Wed 5:00 PM E Due Date: Points Possible: 10 Grade Category: Ho Description: Policies: You can check your ans You can view solutions assignment. You have five attempts You lose 20% of the po answer in your questio at that answer. O eTextbook O Help With This Topic o Web Help & Videos O Technical Support an

Explanation / Answer

let length of the rail covered by the moving wire is meter.

then area through which magnetic flux is linked =A=0.45*x m^2

then magnetic flux=F=magnetic flux density*area

=0.89*0.45*x=0.4005*x Wb

as per faraday's law,emf induced=rate of change of magnetic flux linkage

=dF/dt

=0.4005*(dx/dt)

but dx/dt is the speed of the wire=7.3 m/s

hence magnitude of emf induced=0.4005*7.3=2.9237 volts

part b:

as per lenz's law, the induced current should be such that it would oppose the

magnetic field causing it.

here magnetic field causing the induced emf is directed into the page of paper

hence induced current should be such that induced emf would be directed out of the page of paper.

using right hand thumb rule, we can see that if current is flowing counter-clockwise,

the emf induced will oppose the original magnetic field.

so first option ("counter-clockwise" ) is correct.

part c:

current=emf induced/resistance=2.9237/1.15=2.5423 A

force on the moving wire=current*length*magnetic field*sin(theta)

where theta =angle between direction of field and direction of movement of the rod

=90 degrees
hence force=2.5423*0.45*0.89*sin(90)=1.0182 N

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