As shown in the figure, a wire and a 10- resistor are used to form a circuit in
ID: 1558258 • Letter: A
Question
As shown in the figure, a wire and a 10- resistor are used to form a circuit in the shape of a square, 20 cm by 20 cm. A uniform but nonsteady magnetic field is directed into the plane of the circuit. The magnitude of the magnetic field is decreased from 2.4 T to 0.8 T in a time interval of 90 ms. The average induced current and its direction through the resistor, in this time interval, are closest to
A. 71 mA, from b to a. B. 110 mA, from a to b. C. 43 mA, from a to b. D. 43 mA, from b to a. E. 71 mA, from a to b. 20 cm X X X 20 cm 10Explanation / Answer
emf = d*phi)/dt
flux = phi = BA
emf = d(BA)/dt
emf = AdB/dt
emf = (0.2)^2(2.4-0.8)/0.09
emf = 0.71 V
i = emf/R = 71mA
if the external field is decreases into the page then by lenz's law the induced current opposes that change that is it produces a field into the page
answer is 71mA from b to a
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.