waves Flashcards
(21 cards)
Reflection
When light bounces off a surface.
Law of Reflection
The angle of incidence equals the angle of reflection.
Incident Ray
The incoming ray that hits the surface.
Reflected Ray
The ray that bounces off the surface.
Normal Line
An imaginary line 90° (perpendicular) to the surface at the point where the ray hits.
Specular Reflection
Reflection from a smooth surface (like a mirror), where rays stay organized.
Diffuse Reflection
Reflection from a rough surface, where rays scatter in many directions.
Refraction
The bending of light as it passes from one medium to another.
Why Refraction Happens
Light changes speed in different materials.
Into a Denser Medium (air → water)
Light slows down and bends toward the normal.
Into a Less Dense Medium (water → air)
Light speeds up and bends away from the normal.
Real-Life Example of Refraction
A straw appears bent in a glass of water.
Transverse Waves
Vibrations are perpendicular to wave direction (e.g., light, water).
Longitudinal Waves
Vibrations are parallel to wave direction (e.g., sound).
Wavelength (λ)
Distance between two crests (or troughs).
Frequency (f)
How many waves pass a point in 1 second (measured in Hertz, Hz).
Amplitude
Height from the middle (rest) to the crest of the wave.
Wave Speed Formula
𝑣 = 𝑓 × 𝜆
(Speed = frequency × wavelength)
Diffraction
When waves spread out after passing through a gap or around an object.
When Diffraction Is Strongest
When the gap is about the same size as the wavelength.
Examples of Diffraction
Sound heard around corners, water waves spreading through a gap, light bending slightly through a narrow slit.
