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QLDPhysicsQuick questions
Unit 2: Linear motion and waves
Quick questions on Waves and sound: QCE Physics Unit 2 Year 11
12short Q&A pairs drawn directly from our worked dot-point answer. For full context and worked exam questions, read the parent dot-point page.
What is amplitude?Show answer
maximum displacement from equilibrium. Determines energy.
What is transverse?Show answer
Oscillation perpendicular to propagation direction. Examples: light, water surface, transverse waves on a string.
What is longitudinal?Show answer
Oscillation parallel to propagation. Compressions and rarefactions. Examples: sound, P waves in earthquakes.
What is reflection?Show answer
Wave bounces off boundary. Angle of incidence = angle of reflection.
What is refraction?Show answer
Wave changes direction at boundary between media (different speeds).
What is diffraction?Show answer
Wave bends around obstacles or through openings. Greater when wavelength comparable to opening.
What is interference?Show answer
Two waves superpose: constructive (in phase) and destructive (out of phase).
What is polarisation?Show answer
Only transverse waves. Light passing through polariser: $I = I_0 \cos^2 \theta$ (Malus's law).
What is confusing wave types?Show answer
Light is transverse; sound is longitudinal.
What is forgetting medium for sound?Show answer
Sound requires a medium; cannot travel through vacuum.
What is mixing $v$ and $c$?Show answer
Light in vacuum: $c$. Light in medium: $c/n$ where $n$ is refractive index.
What is doppler direction?Show answer
Approaching: higher frequency. Receding: lower.