Waves, Optics, and the Electromagnetic Spectrum Flashcards

Grade 12 · Science · Flashcards

Key vocabulary for waves, optics, and the EM spectrum for Grade 12 Science.

Flashcards

Wavelength (λ): Distance between two consecutive wave crests; measured in meters or nanometers.
Frequency (f): Number of wave cycles per second; measured in hertz (Hz).
Wave speed: v = fλ; speed of light in vacuum = 3 × 10⁸ m/s.
Electromagnetic wave: Transverse wave with oscillating electric and magnetic fields; travels through vacuum at speed c.
Photon: A quantum (particle) of electromagnetic radiation; energy E = hf.
Refraction: Bending of waves when crossing between media of different density/refractive index.
Snell's Law: n₁ sin θ₁ = n₂ sin θ₂; governs direction of refracted ray at interface between media.
Total internal reflection: When light exceeds the critical angle inside a denser medium and reflects entirely back; basis of fiber optics.
Convex lens: Converging lens that brings parallel light rays to a focal point; used in cameras, magnifiers, correcting farsightedness.
Concave lens: Diverging lens that spreads light rays; used to correct nearsightedness (myopia).
Diffraction: Spreading of waves through narrow openings; most noticeable when λ ≈ opening width.
Doppler effect: Apparent change in wave frequency due to relative motion between source and observer.