If the metal bob of a simple pendulum is replaced by a wooden bob, then -

Concept:

Simple Pendulum: 

An ideal simple pendulum consists of a heavy point mass body (bob) suspended by a weightless, extensible, and perfectly flexible string from rigid support about which it is free to oscillate.

The time period of a simple pendulum:

⇒ It is given as 

\(T= 2\pi\sqrt\frac{L}{g}\)     

where T= time period​, L= length of the string, g= acceleration due to gravity.

The only things that affect the period of a simple pendulum are its length and acceleration due to gravity.

The period is completely independent of other factors, such as mass.

Hence even after changing the mass or material of the bob from metal to wood, the time period will remain T.