Properties of Light

Frequency is defined as the number of cycles per second, and this unit is named the hertz (Hz) in honor of Heinrich Hertz. Joules measure energy, Newtons measure force, and Amperes measure current.

Frequency measures the rate of repetition of a wave cycle over time. Wave period is the time for one cycle, and amplitude relates to the height of the wave.

Wavelength is the spatial distance between consecutive corresponding points on a wave, such as crest to crest or trough to trough.

Amplitude represents the maximum displacement of a point on a wave from its equilibrium or resting position. It is often associated with the intensity or loudness of a wave.

The colors seen on a soap bubble are caused by thin-film interference, where light waves reflecting off the inner and outer surfaces of the film overlap and interfere constructively or destructively.

Interference occurs when two or more waves overlap in the same space. Constructive interference reinforces the waves, while destructive interference cancels them out.

The color of an object is determined by which wavelengths of light are reflected and which are absorbed. The speed of light is constant in a given medium and does not determine the color of an object.

Refraction is the bending of a wave as it passes from one medium to another, caused by a change in the wave's speed. Reflection is bouncing off a surface, and scattering is light spreading in many directions.

Reflection occurs when light waves strike a surface and bounce back into the original medium. This is the principle behind mirrors.

The Sun emits a vast amount of electromagnetic radiation across the spectrum, which is the primary energy source for Earth. While bulbs and flashlights produce light, they are not the primary source for the planet.

Radiation is the transfer of energy through electromagnetic waves, which can travel through a vacuum. Unlike conduction or convection, it does not require matter to transfer energy.

James Clerk Maxwell formulated the classical theory of electromagnetic radiation, bringing together electricity, magnetism, and light as manifestations of the same phenomenon and predicting the speed of light.

When light travels through a medium like glass or water, it interacts with the particles of the medium, which causes the wave to slow down compared to its speed in a vacuum.

The speed of light in a vacuum is a universal physical constant, approximately 300,000,000 meters per second (or 3 x 10^8 m/s).

Electromagnetic waves, including light, are unique because they do not require a material medium to propagate; they can travel through the vacuum of space.

Electromagnetic waves are composed of oscillating electric and magnetic fields that are perpendicular to each other and to the direction of wave propagation.

A wave is fundamentally a disturbance that travels through space and matter, transferring energy from one point to another without the net transfer of matter.

Light propagates as electromagnetic waves. While we often model light as rays (straight lines) for simplicity in optics, its fundamental nature is wave-like.