Question

why do we take small oscillation while measuring time period​

Answer 1

Answer:

Some small oscillations are visible in the PBM prediction for the number of undifferentiated cells and viable (total) cells. The period of these damped oscillations corresponds to the length of the cell cycle of the undifferentiated cells.

Answer 2

Answer:

Lets assume that we want to calculate the time period of a pendulum undergoing oscillations. Now, we need to make sure that the oscillations of the bob of the pendulum needs to be small.

Explanation:

so this is your answer...