Wave, Sound, and Light Physics Concepts
Wave Fundamentals
Wave Definition
A disturbance traveling through a material medium due to the vibration or oscillation of its particles.
Wave Types by Medium
- Mechanical Waves: Require a medium (natural environment) for propagation.
- Electromagnetic Waves: Do not require a medium; can travel through a vacuum.
Wave Types by Direction
- Transverse Waves: Particles vibrate perpendicular to the direction of propagation, forming peaks and valleys.
- Longitudinal Waves: Particles vibrate in the same direction as propagation, forming compressions and expansions.
Sound Waves
Sound Definition
A longitudinal and mechanical wave that originates from the vibration of bodies and can be reflected and refracted.
Audibility Ranges
- Audible Sound: Frequencies from 20 Hz to 20,000 Hz.
- Inaudible Sound: Includes infrasound (below 20 Hz) and ultrasound (above 20,000 Hz).
Wave Characteristics
Amplitude
The height of a crest (ridge) or the depth of a trough from the equilibrium point, or the maximum displacement in a compression.
Period
The time it takes for a wave to complete one full oscillation or cycle.
Frequency
The number of oscillations or cycles completed by a wave in one second.
Sound Phenomena
Echo
A phenomenon produced by the reflection of sound waves.
Sound Intensity
Relates to the amplitude of the sound wave:
- Loud Sounds: Characterized by large amplitude.
- Soft Sounds: Characterized by small amplitude.
Sound Tone (Pitch)
Relates to the frequency of the sound wave:
- Low-Frequency Sounds: Perceived as low pitch.
- High-Frequency Sounds: Perceived as high pitch.
Timbre
The quality that distinguishes different sounds, even if they have the same intensity and pitch.
Loudness
The subjective sensation produced in the ear when perceiving a certain sound intensity.
Light Waves
Light Definition
A form of energy originating from luminous objects, whose waves are transmitted through a vacuum or transparent media.
Light Phenomena
Reflection of Light
The phenomenon whereby light rays are deflected when reaching a surface.
Laws of Reflection
- The incident ray, the reflected ray, and the normal to the surface all lie in the same plane.
- The angle of incidence (i) is equal to the angle of reflection (r). (i = r)
Refraction of Light
The phenomenon by which light waves are deflected when passing from one propagation medium to another, where they travel at different speeds.
Critical Angle
The angle of incidence for which the angle of refraction is 90 degrees.
Total Internal Reflection
Occurs when the angle of incidence is greater than the critical angle, causing all incident rays to be totally reflected back into the original medium.
Optical Devices
Lenses
A transparent and homogeneous isotropic medium, typically limited by two curved surfaces or one flat and one curved surface.
Types of Lenses
- Convergent Lenses: Used to correct hyperopia (farsightedness).
- Diverging Lenses: Used to correct myopia (nearsightedness).
Plane Mirrors
Polished surfaces that produce virtual images that are symmetrical and equal in size to the object.