Question

In the figure, a 170-tum coil of radius 3.2 cm and resistance 5.8 is coaxial with a solenoid of 200 turns/om and diameter 4.5 cm. The solenoid current drops from 1.5 A to zero in time interval A - 29 ms. What current is induced in amperes in the col during ? Cil Number Unit the tolerance +/-29

Answer 1

Solution) N = 170

r = 3.2 cm = 3.2×10^(-2) m

R = 5.8 ohm

Ns = 200 turns/cm = 200×10^(2) turns/m

ds = 4.5 cm = 4.5×10^(-2) m

di = 1.5 A

delta t , dt = 29 ms = 29×10^(-3) s

i = ?

E = - N(d(phi)/dt)

phi = B.A

B = (Uo)(Ns)(i)

E = - ((N)(Uo)(Ns)(As)(di/dt)

Uo = 4(pi)×10^(-7)

As = (pi)(rs^2)

rs = (ds/2) = (4.5/2) = 2.25 cm = 2.25×10^(-2) m

E = - [(170)(4(pi)×10^(-7))(200×10^2)(pi)((2.25×10^(-2))^2)(0-1.5)]/(29×10^(-3))

E = 0.35 V

i = (E/R)

i = (0.35)/(5.8)

i = 0.060 A