GED Science TestPhysical ScienceHard
A student is investigating the phenomenon of resonance in a simple pendulum. They find that by applying small, periodic pushes to the pendulum at its natural frequency, its amplitude of swing increases significantly. What is the fundamental principle illustrated by this observation?
- ADamping
- BReflection
- CRefraction
- DResonance
Show answer & explanationAnswer & explanation
Correct answer: D. Resonance
Resonance occurs when an oscillating system (like a pendulum) is driven by an external force at its natural frequency, leading to a significant increase in its amplitude of oscillation. The student's observation directly describes this principle.
Why the other options are wrong
- A. Damping is the reduction in amplitude of oscillations due to energy loss, the opposite of what's observed.
- B. Reflection is the bouncing back of a wave from a surface, not related to increasing amplitude in an oscillating system.
- C. Refraction is the bending of waves as they pass from one medium to another, not relevant to a pendulum's swing amplitude.
Resonance
A phenomenon where an oscillating system responds with maximum amplitude when excited by an external force at its natural (resonant) frequency.
- Requires a driving force at natural frequency
- Leads to a large amplitude of oscillation
- Can be constructive or destructive (e.g., shattering glass with sound)
Memory trick: Resonance hits the right note, making the swing grow.