Electromagnetic Energy

Isaac Newton

English physicist proposed the corpuscular (particle) view of light and showed white light contains the colors of the rainbow

Corpuscular view of light

Newton’s theory that light consists of tiny particles

Christiaan Huygens

Dutch Mathematician who proposed that light behaves as waves

Luminiferous aether

A hypothetical medium once believed necessary for light waves to travel through space

Thomas Young

English physicist who demonstrated interference patterns from light passing through closely spaced slits.

Interference

Phenomenon that occurs when two or more waves overlap and interact

James Clerk Maxwell

Scottish physicist who developed electromagnetic theory showing light is electromagnetic radiation.

Classical mechanics

Framework describing matter as particles obeying Newton’s laws.

Classical electrodynamics

Framework describing electromagnetic radiation as waves governed by Maxwell’s equations

Wave-particle duality

The concept that light exhibits both wave-like and particle-like behavior

Wave

An oscillation that transports energy from one point in space to another

Amplitude

The maximum displacement of a wave from equilibrium.

Hertz

Unit of frequency equal to one cycle per second

intensity

Wave amplitude is related to wave _________

Brightness

Light’s intensity

Loudness

Sound’s intensity

AM

Radio transmission method in which amplitude varies while frequency stays constant

FM

Radio transmission method in which frequency varies while amplitude stays constant.

Amplitude Modulation

Fullform of AM

Frequency Modulation

Fullform of FM

Constructive interference

Occurs when peaks align with peaks (or troughs with troughs), producing greater intensity

Destructive interference

Occurs when peaks align with troughs, reducing intensity

Stationary waves

Synonym for standing waves

Standing waves

Waves confined to a region rather than traveling are called

Quantization in standing waves

Only discrete standing-wave patterns are allowed

Node

A point in a standing wave where no motion occurs.

n − 1

Number of nodes in a standing wave

Radial nodes

Circular nodes in two-dimensional standing waves.

Angular nodes

Nodal lines (radii) in two-dimensional standing waves

Blackbody

An ideal emitter that approximates the radiation behavior of heated materials

Blackbody spectrum

Distribution of emitted radiation from a blackbody as a function of wavelength

λmax

Wavelength at which blackbody radiation intensity is maximum

Shifts to shorter wavelengths

As temperature increases, λmax….

Ultraviolet catastrophe

Failure of classical physics predicting infinite intensity at short wavelengths

Max Planck

German physicist who resolved the ultraviolet catastrophe by introducing quantized energy

Planck quantization equation

E = nhν

n

Symbol inside the Planck’s quantization equation that represents the integer quantum number

Photoelectric effect

Emission of electrons from a metal when light above threshold frequency strikes it

Threshold frequency

Minimum frequency required to eject electrons

Albert Einstein

German physicist who explained the photoelectric effect using photons.

number of photons

According to Albert Einstein, Photon intensity depends on ________________, not wave amplitude

Endothermic process

Process involving absorption of light

Exothermic process

Process involving emission of light

Dorothy Crowfoot Hodgkin

i) Used X-ray crystallography to determine structures of important biomolecules
ii) Recieved 1964 Nobel Prize in Chemistry
iii) Determined the Insulin structure in 1969

X-ray crystallography

Technique using X-ray diffraction to determine molecular structure.