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As shown in the figure below, a coil that is square, has 30 turns, is 0.82 ?, an

ID: 1400266 • Letter: A

Question

As shown in the figure below, a coil that is square, has 30 turns, is 0.82 ?, and is 14.0 cm on a side is between the poles of a large electromagnet that produces a constant, uniform magnetic field of 0.5 T directed into the page. As suggested by the figure, the field drops sharply to zero at the edges of the magnet. The coil moves to the right at a constant velocity of 3.00 cm/s. What is the current through the coil wire in the following instances?

(a) before the coil reaches the edge of the field
A

(b) while the coil is leaving the field
A

(c) after the coil leaves the field
A

(d) What is the total charge that flows past a given point in the coil as it leaves the field?
C

Explanation / Answer

given,

no.of turns N=30

resistance of coil R=0.82 ohm

side length of coil, l=14 cm

area of the coil A = l^2 = 196*10^-4 m^2

magnetic field B=0.5 T

velocity of the coil v=3 cm/sec

a)

induced curent i = emf/R

= N*dB/dt

= 0 A


b)


induced current i= emf/R

= l*V*B/R

= (14*10^-2)*(3*10^-2)*(0.5)/0.82

= 2.59*10^-3 A

= 2.59 mA


c)

induced curent i = emf/R

= N*dB/dt

= 0 A

d)

charge q=N*change in flux/R

= N*B*A/R

= 30*0.5*196*10^-4/0.82

= 0.36 C