Explanation
if the phase of vibration Θ = π/ z radians, and you are saying that a quarter of the cycle is completed
Then we can equate these two conditions to find the value of z.
In Simple Harmonic Motion (SHM), one complete cycle corresponds to 2π radians. Therefore, if Θ = π/ z radian represented a quarter of the cycle, then we can write:
Θ = π/ z = 1/ 4 x 2 π
simplifying
π/ z = π/ 2
Now, to find the value of z, we can cross-multiply
z = 2
So, when the phase of vibration Θ = π/ z radians and a quarter of the cycle is completed, the value of z is 2.