A uniform rod of mass $m$ and length $l$ is hinged at one of its ends with the ceiling and another end of the rod is attached with a thread which is attached to the horizontal ceiling at point P. If one end of the rod is slightly displaced horizontally and perpendicular to the rod and released, the period of small oscillation is $2\pi \sqrt{\frac{2l sin \theta }{xg}}$. Find $x$.