All of the questions relate to the loop in the picture shown right. A rectangula
ID: 779341 • Letter: A
Question
All of the questions relate to the loop in the picture shown right. A rectangular conducting loop of mass m =0.20 kg and width w 0.30 m falls xlxx xxx vertically downward at constant velocity of 8.0 m/s. A partial cross section ofx xx the loop is within a horizontal uniform magnetic field that is directed into the page and is of magnitude B 3.5 T. In the figure, h represents the height of the top edge of the loop above the bottom of the region where the field exists; h decreases as the loop falls. Using Lenz's Law determine the direction of the induced current through resistor R across the bottom edge of the loop as the loop falls. (Choose the best answer-3 points) (A) To the right (i.e.counter-clockwise around the loop). (B) To the left (i.e. clockwise around the loop). 1.
Explanation / Answer
as the loop falls the magnetic flux decreases
the induced magnetic field is into the page
by right hand rule the induced current is clockwise in the loop
the current in the resistor is To the left
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3)
magnetic flux = B*A = B*w*dh
induced emf = rate of change in flux
emf = B*w*dh/dt
emf = B*w*v
emf = 3.5*0.3*8 = 8.4 V