The bob of a pendulum takes 0.50 seconds to go from one extreme position to the mean position. Calculate the time period of the pendulum.

If the time taken by one pendulum to reach its mean position from the extreme position is 0.25 seconds then a pendulum will move to two extreme positions from one mean position only. That will means that the total time period = 2 * 0.25 = 0.50 seconds.

b.a device that inputs heat into a cool object