A uniform rod PQ of length `I` and mass m is placed on a smooth horizontal surface. It is hinged at one of its ends and touches the conducting circular loop at another end. The system is subjected to vertical magnetic field `B_(0)`. Rod is given angular velocity `omega_(0)` about the axis passing through P. If the time after which its angular velocity becomes half is `(a)/(b)(mRln2)/(B^(2)t^(2))` . Find the value of `(a + b)`, where a and b are smallest positive integers.

Answer

7