Deck 'A' Flashcards
What is the electromagnetic spectrum?
The range of all possible frequencies of electromagnetic radiation.
How are electromagnetic waves emitted?
Emitted when electrically charged particles change energy levels (electrons or nucleons).
What is characteristic radiation?
When an electron changes to a lower orbit.
What is an electromagnetic wave?
The moving wave effect produced by oscillating electric and magnetic fields a right angle to the direction of travel and each other.
What kind of wave is an electromagnetic wave?
A progressive transverse wave.
What is frequency?
The number of oscillations that pass a given point in a specified period of time.
What is wavelength?
The distance measured between two successive points in the wave.
What is the inverse square law?
Intensity decreases as constant energy becomes spread over a larger area at distance.
What suggests that light is a wave?
- Diffraction
- Interference
- Polarisation
What suggests that light is a particle?
The photoelectric effect - electromagnetic waves carry energy, so energy can be absorbed by matter.
Describe diffraction.
The process of waves spreading out after passing through a narrow space.
Describe interference.
When two or more waves result in a new wave pattern.
Describe polarisation.
The process where electromagnetic waves are restricted to certain directions of travel.
Describe the photoelectric effect.
Some frequencies of light give electrons on a metal’s surface enough energy to be freed. This is due to the electrons absorbing energy that makes them vibrate.
Describe radio waves.
- Longest wavelength
- Transfer information far
- Used in MRI
