How will the time period of simple pendulum change when the bob is replaced by another bob of I same mass and larger size is same size and of larger mass?

(b) remain same

The time period of a simple pendulum is

`T=2pisqrt(l/g)`

where l = length of the pendulum

g = acceleration due to gravity

Therefore, from the given equation, we know that the periodic time of the pendulum does not depend on the mass of the bob, and so, it does not matter of what material the bob is made of, and hence, its time period remains the same.