A magnetic field is perpendicular to the plane of a single-turncircular coil. The magnitude of the field is changing, so that anemf of 0.82 V and a current of3.0 A are induced in the coil. The wire isthe re-formed into a single-turn square coil, which is used in thesame magnetic field (again perpendicular to the plane of the coiland with a magnitude changing at the same rate). What emf andcurrent are induced in the square coil? emf Enter anumber. 1 V current Enter anumber. 2 A Enter anumber. Enter anumber. emf Enter anumber. 1 V current Enter anumber. 2 A
Explanation / Answer
from Faraday's Law of induction: -B/t*area=emf resistance R=0.82/3=0.273 1st case: A=r2 2nd case: A'=(r/2)2 =A/4 => emf ' =0.82*/4=0.644 V => I=2.36A 2nd case: A'=(r/2)2 =A/4 => emf ' =0.82*/4=0.644 V => I=2.36A