Two pendulums have time periods T and 5T/4. They start S.H.M. at the same time from the mean position. What will be the phase difference between them after the biggerpendulum has complete one oscillation?

As 5T4=T+T4By the time, the bigger pendulum makes one full oscillation, the smaller pendulum will make 1+14 oscillation. The bigger pendulum will be in the mean position and the smaller one will be in the positive extreme position. Thus, phase difference = 90o