Electromagnetic Waves and light

Photon

A light particle released when an electron falls from a higher to a lower energy level.

Electromagnetic Radiation

Energy that travels as waves, including radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays, and gamma rays.

Crest

The highest point of a wave.

Amplitude

Distance from the rest position to the crest, indicating wave intensity.

Wavelength (λ)

Distance between two consecutive crests of a wave.

Frequency (f)

The number of wave cycles passing a point each second, measured in hertz (Hz).

Relationship between Wavelength and Frequency

Short wavelength correlates with high frequency, while long wavelength correlates with low frequency.

Electromagnetic Spectrum

A range of electromagnetic radiation categorized by wavelength, frequency, and energy.

Radio Waves

Electromagnetic waves with the longest wavelengths, lowest frequencies, and lowest energies.

Energy of Electromagnetic Waves

Energy (E) is directly proportional to frequency (f), given by the equation E=hf.

Blackbody Radiation

A body that absorbs all incoming radiation and re-emits radiation based on its temperature.

Fluorescence

The process where a substance absorbs light and immediately emits light of longer wavelength.

Light Emitting Diodes (LEDs)

Devices that emit light in specific energy bands and are very energy efficient.

Visible Light

The portion of the electromagnetic spectrum that is detectable by the human eye, ranging from 400 nm to 700 nm.

Infrared Radiation (IR)

Electromagnetic radiation located between microwaves and visible light, emitted by warm objects.

Ultraviolet Radiation (UV)

Electromagnetic radiation located between visible light and X-rays, with types ranging from UVA to UVC.

Effects of UV Radiation

Benefits include vitamin D production; risks include sunburn, skin damage, and skin cancer.

Incandescent Light Bulbs

Light bulbs that produce visible light through blackbody radiation, but are inefficient due to high infrared radiation emission.

Key Fact: Electrons and Photons

Electrons emit photons when they drop to lower energy levels.

Speed of Light

Electromagnetic waves travel at a speed of 2.998 × 10⁸ m/s in a vacuum.

Inversely Related

Wavelength and frequency are inversely related, meaning as one increases, the other decreases.

Directly Related

Frequency and energy are directly related; higher frequency means higher energy.

SPF

Sun Protection Factor; higher SPF means greater UV protection.