Question

A five-turn circular wire coil of radius 0.425 m lies in a plane perpendicular to a uniform magnetic field of magnitude 0.370 T. If the wire is reshaped from a five-turn circle to a three-turn circle in 0.101 s (while remaining in the same plane), what is the average induced emf in the wire during this time?

Answer 1

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A three-turn circular wire coil of radius 0.585 m lies in a plane perpendicular to a uniform magnetic field of magnitude 0.335 T. If the wire is reshaped from a three-turn circle to a two-turn circle in 0.111 s (while remaining in the same plane), what is the average induced emf in the wire during this time?

length of wire= 3*2?*r= 11.026 m

for a two turn circle

2?*r= 11.026/2= 5.513

new r2= 0.8775 m

initial flux= BA1= 0.335* (?*0.585*0.585)= 0.360

final flux= BA2= 0.335* (?*0.8775*0.8775)= 0.810

induced emf ?= N?2-N?1/?t= 1.62-1.08/0.111= 4.864 V