Question

Part 3..PHY2...16

A conducting ring is in a uniform magnetic field B as shown. The ring has a radius of r = 50 cm and an effective resistance of R = 0.10 Ohm. The magnitude of B deceases steadily from an initial value of B_0 = 0.042 T to zero in 0.20n seconds, and stays at zero afterwards Find the magnitude of the induced emf in the ring What is the current in the ring? And in what direction (briefly explain)? At what rate is energy being converted into thermal energy? Sketch the induced emf as a function of time from 0 to 0.5 s. Briefly explain your graph. magnetic field B stays the same, should the radius r grow or shrink so as to induce the same current as Find r as a function of t in order to produce a steady current as above at constant B_0.use back, of necessary).

Answer 1

given that,

radius,r=50 cm=0.05 m

resistance,R=0.10 ohm

magnetic field, B0=0.042 T

time, t=0.20 s

a)

e=-N$\Delta \phi$/$\Delta$t

=-BA/t

=Bpir²/t

=(0.042 T*3.14*0.05 m*0.05 m)/(0.20 s)

=0.16485 V

b)

e=IR

I=e/R

=(0.16485 V)/(0.10 ohm)

=1.6485 A