Induced EMF and Current in a Shrinking Loop ® 12 of 19 > Constants | Periodic Ta
ID: 1873689 • Letter: I
Question
Induced EMF and Current in a Shrinking Loop ® 12 of 19 > Constants | Periodic Table Y Part A Shrinking Loop. A circular loop of flexible iron wire has an initial circumference of 164 cm, but its circumference is decreasing at a constant rate of 12.0 cm/s due to a tangential pull on the wire. The loop is in a constant uniform magnetic field of magnitude 0.800 T, which is oriented perpendicular to the plane of the loop. Assume that you are facing the loop and that the magnetic field points into the loop. Find the magnitude of the emf & induced in the loop after exactly time 9.00 s has passed since the circumference of the loop started to decrease. Express your answer numerically in volts to three significant figures. · View Available Hint(s) Vo Az¢ 6 + ? &= 2.22 • 1072 Submit Previous Answers X Incorrect;Try Again; 3 attempts remaining Y Part B Find the direction of the induced current in the loop as viewed looking along the direction of the magnetic field. • clockwise O counterclockwise Submit Previous AnswersExplanation / Answer
a)
Circumference is given by
C=2pir
dC/dt =2pi*dr/dt =-0.12 m/s
Area is given by
A=pir2 =(2pi*dr/dt)*r=-0.12r
In 9 s Circumference decreases by 0.12*9 =1.08 m,
Radius after 9 s is
r =(1.64-1.08)/2pi =0.08913 m
Induced emf
E=-BdA/dt =-0.8*(-0.12*0.08913)
E=8.556*10-3 Volts
b)
Clockwise