A conducting light string is wound on the rim of a metal ring of radius `r` and mass `m`. The free end of the string is fixed to the ceiling. A vertical infinite smooth conducting plane is always tangent to the ring as shown in the figure. A uniform magnetic field Bis applied perpendicular to the plane of the ring. The ring is always inside the magnetic field. The plane and the strip are connected by a resistance `R`. When the ring is released, find

a. the curent in the resistance `R` as as function of time.
b. the terminal velocity of the ring.