Question

Which of the following would not affect the period of a simple harmonic oscillator? A. changing a pendulum's length B. changing the mass attached to a spring C. changing the amplitude of oscillations D. changing out the spring while keeping the same mass

Answer 1

Time period of a pendulum is
   
where, L is the length of the pendulum. So, if the length L changes, then, the period T also changes. So, option (A) is not correct.

For a mass m attached to a spring of spring constant k, the time period is given by
  
And so, changing the mass m, changes the time period T. So, option (B) is not correct.
Changing the spring changes k and so, changes the time period. And so, option (D) is not correct.

And the time period in both the cases does not depend upon the amplitude of oscillations. So, changing the amplitude of oscillations does not change the time period T.
So, option (C) is correct.