JEE Advanced 2020 Full Test 7 Paper 1

A solid sphere of radius r and mass m is released from point A on a vertical circular surface of radius 5r which has sufficient friction in part AB. Part BCD is smooth and h is the maximum height attained by the centre of the sphere from point C in part CD. The total energy and the kinetic energy at this height is T and K, respectively (assume that a lowest point C of the circular path as reference point for potential energy). Then