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The magnetic field through the rectangular loop shown in the figure changes acco

ID: 1471936 • Letter: T

Question

The magnetic field through the rectangular loop shown in the figure changes according to the relation B(t)= (1200- 31.0t^2) T with t in seconds. The resistance of the loop is 6.22 milli Ohms. Based on the above information, which statement(s) is (are) TRUE.

(a) At t=4.8 s, the magnetic flux is decreasing.

(b) At t= 4.8 s, the magnetic flux is increasing.

(c) At t=4.8 s, the induced current in the rectangular loop is non zero and is clockwise.

(d) At t=4.8 s, the induced current in the rectangular loop is non zero and counterclockwise.

(e) This problem is on Faraday's Law.

Explanation / Answer


magnetic flux = phi = B*A
from Farady law

emf = rate of change in flux = (d/dt)*(B*A)

emf = A*(dB/dt) = 0.256*0.194*-62t = -3.71t

current = e/R = 3.71t/(6.22*10^-3) = 596.46*t A


at t = 4.8 s


flux = 62*4.8 = 297.6 Tm^2

as the flux is increasing the direction is clock wise

current = i = 2863 A

(b) At t= 4.8 s, the magnetic flux is increasing.


(c) At t=4.8 s, the induced current in the rectangular loop is non zero and is clockwise

(e) This problem is on Faraday's Law