Summary Topic 6b - EM Spectrum

Produced using an alternating current

When radio waves reach a receiver, the waves are absorbed
and the enegry transferred.

This causes the electrons in the receives to oscillate,
producing a current the same frequency as the radio waves
that generated it Radio Waves

Long Wave - Can be transmitted and received halfway round the
world. Used in internaitonal TV/ Radio

Short Wave - Reflected between the Eart and the ionoshpere.
Used in bluetooth
Uses
TV signals and FM radio - Very short wavelength, to get
reception you muct be in direct sight of the transmitter

Certain wavelngths can pass easily through the earth's atmostphere Communication
The satellite transmits data to and from Earth and firects it to a
diferent direction
Microwaves
Microwave ovens

Have wavelengths which allow them to be absorbed by water
molecules in food
Cooking
Microwaves can heat water, so they can heat water inside our
bodies, which can damage them
T
IR radiation is given out by all objects, the hotter the object, the
more radiation it gives out IR cameras
IR cameras can be used to detect IR Radiation

Heat can be colour coded showing different amounts of IR