'A long horizontal rod has a bead which can slide along its length, and initially placed at a di...

"A long horizontal rod has a bead which can slide along its length, and initially placed at a distance \( L \) from one end of \( A \) of the rod: The rod is set in angular motion about \( A \) with constant angular acceleration \( \alpha \). If the coefficient of friction between the rod and the bead is \( \mu \) and gravity is neglected, then the time after which the bead starts slipping is :
(A) \( \sqrt{\frac{\mu}{\alpha}} \)
(B) \( \frac{\mu}{\sqrt{\alpha}} \)
(C) \( \frac{1}{\sqrt{\mu \alpha}} \)