LIGHT GEN SCI T1

Electromagnetic energy

Energy that allows us to see objects; it can travel through a vacuum without a medium and behaves as particles called photons.

Reflection

The bouncing back of light or a wave after hitting a surface instead of passing through it.

Law of Reflection

Angle of Incidence = Angle of Reflection.

Angle of Incidence

The angle between the incoming ray and the normal.

Angle of Reflection

The angle between the reflected ray and the normal.

Specular Reflection

Reflection that occurs on smooth surfaces and produces a clear image.

Diffuse Reflection

Reflection that occurs on rough surfaces where light is scattered in different directions.

Refraction

The bending of light as it passes from one transparent medium to another.

Less Dense

Dense: Light slows down and bends toward the normal.

Dense

Less Dense: Light speeds up and bends away from the normal.

Dispersion

The separation of white light into its different colors because each color bends by a different amount.

Diffraction

The spreading or bending of light waves around obstacles or through narrow openings.

Interference

The overlapping of two or more light waves that produces brighter or darker regions.

Polarization

The process of restricting light waves so that they vibrate in only one direction.

Rectilinear Propagation

The principle that light travels in straight lines through a uniform medium.

Prism

A transparent optical object made of glass or plastic with flat, polished surfaces that refract, reflect, or disperse light.

Triangular Prism

The most common type of prism, having a triangular cross-section.

Spectrum

A band of colors produced by dispersion.

ROYGBIV

Red → Orange → Yellow → Green → Blue → Indigo → Violet.

Red Light

The color of visible light that bends the least in dispersion.

Violet Light

The color of visible light that bends the most in dispersion.

Total Internal Reflection (TIR)

Reflection that occurs when light travels from a denser medium to a less dense medium and strikes the surface at an angle greater than the critical angle.

Conditions for TIR

Light must travel from a denser medium to a less dense medium, and the angle of incidence must be greater than the critical angle.

Rainbow Formation

Sunlight enters water droplets, is refracted and dispersed, undergoes internal reflection, and exits through refraction again.

Electromagnetic Spectrum

The complete range of all types of electromagnetic radiation.

Electromagnetic Waves

Transverse waves that can travel through a vacuum at approximately 3 × 10⁸ m/s.

Increasing Wavelength

Decreasing frequency and energy.

Decreasing Wavelength

Increasing frequency and energy.

Binoculars

Optical instruments that use prisms to reflect light multiple times, correct the inverted image, shorten the optical path, and produce brighter images through total internal reflection.

Periscopes

Optical instruments that allow a person to see over or around obstacles using two right-angle prisms or mirrors.

Cameras

Devices that may use a pentaprism to reflect light several times and correct the upside-down image formed by the lens.

Spectrometer

An instrument used to separate light into its component wavelengths and analyze them.

Amplitude

The maximum distance a wave moves from its rest position.

Wavelength

The distance between two consecutive crests or two consecutive troughs.

Frequency

The number of waves that pass a point in one second.

Speed

The rate at which a wave travels through a medium.