Final answer:
The damping of the oscillator can be inferred as moderate because the amplitude decreases to 60% in 50 seconds, indicating a significant but not complete reduction of oscillation, typical of an underdamped system.
Step-by-step explanation:
The question concerns the damping of an oscillator which is a concept in Physics. Given that the oscillation of the oscillator decreases to 60% of its initial amplitude in 50 seconds when air is admitted into the vacuum chamber, we can infer that there is a significant damping effect on the oscillator. This change indicates that the damping force exerted by the air reduces the amplitude of oscillations over time, eventually converting the mechanical energy into thermal energy.
Answering the question, since the oscillation decreases significantly (to 60% in 50 seconds), the correct choice would be B. The damping is moderate. This is because the oscillator still continues to oscillate but with a significant decrease in amplitude, which is characteristic of an underdamped system. This situation is unlike heavy damping (or overdamping), where the amplitude would reduce much more rapidly, or negligible damping, where the amplitude reduction would be minimal over such a time frame.