SCIENCE 10 (ELECTROMAGNETIC WAVES) 4TH QTR

william gilbert

- coined the term "electricus" to describe materials that attracted small objects

- laid the foundation for the study of electricity and magnetism

hans christian orsted

- discovered that an electric current is surrounded by magnetic field

- current-carrying wire produces a magnetic field

michael faraday

- electromagnetic induction

- father of electromagnetism

- discovered that a moving wire through a magnetic field could produce an electric current

joseph henry

current produced by magnetic field is an induced current

james clark maxwell

- describe how electric and magnetic fields interact and how they move through space as waves

- electromagnetic waves travel at the speed of light, meaning light itself is an electromagnetic wave

heinrich hertz

he proved the existence of radiowaves

speed of light

3 x 10⁸ m/s

mechanical wave

requires a medium to travel or propagate

electromagnetic waves

- transverse waves, meaning that the oscillations of the electric and magnetic fields are perpendicular to the direction of wave propagation

- can travel through a vacuum and do not require a medium

crest

- highest point of the wave above the equilibrium position

- peak of the wave where enegry is concentrated

trough

- lowest point of the wave below the equilibrium position

- medium are displaced the most in the opposite direction to the crest

amplitude

- the maximum displacement of a point from its equilibrium position

- measures how far the particles of the medium move

wavelength

- distance between two consecutive crests or troughs

- length of one complete wave cycle

- measured in meters

frequency

- number of complete wave cycles pass a given point

- typically measured in hertz (hz)

- inversely related to wavelength

node

a point where the wave has zero amplitude

electromagnetic radiation

refers to the energy that is emitted or radiated by charged particles in the form of electromagnetic waves

electromagnetic spectrum

refers to the entire range of electromagnetic radiation

radio waves

- longest wavelengths, lowest frequencies

- low energy level

- non-ionizing radiation

microwaves

- shorter wavelengths and higher frequencies than radio waves

- energy is higher than radio waves but lower than infrared

- non-ionizing radiation

infrared

- longer wavelengths than visible light but shorter than microwaves

- aka heat radiation

- non-ionizing radiation

visible light

- small portion of the spectrum detectable by the human eye

- allows us to see the world around us

ultraviolet

- shorter wavelengths and higher frequencies than visible light

- non-ionizing

xrays

- higher energy and shorter wavelengths than uv

- ionizing

gamma rays

- highest energy, have very high frequency and shortest wavelength

- ionizing radiation

non-ionizing

does not have enough energy to ionize atoms or molecules