Unit 2: Waves and Radiation Flashcards
What is a Wave?
Something that transfers energy from one point to another
Transverse Wave
Particles of the medium vibrate at right angles to the direction the energy travels.
Examples: E-M Waves + Water Waves
Longitudinal Waves
Energy travels along in the same direction as the particles vibrate.
Example: Sound Waves
Wavelength
DIstance from a point to the point the wave begins to repeat itself. Could be from peak to peak or trough to trough. Measured in metres(m) and has the symbol λ
Frequency
Number of waves produced in 1 second by the source producing the wave. Measured in Hertz(Hz) and has the symbol f
Amplitude
Half the distance from peak to trough or the height of the wave from rest position. Measured in metres(m)
Wave Speed
How quickly the wave travels from its source. Is value is the same as distance travelled in one second. Measured in metres per second(ms-1) and has the symbol v
Period
Time taken for one complete wave to be produced. Also time taken for one whole wave to pass a point. Measured in seconds(s) and has the symbol T
Speed of Sound in Air
340 ms-1
Speed of Light in Air
3x108 ms-1
Diffraction
The spreading out of waves when they go through a gap or past the edge of a barrier
The greater the wavelength, the greater the diffraction
Electromagnetic Spectrum
Consists of a group of radiations that all travel at the speed of light
Visible Spectrum
Consists of a range of different colours of light that the human eye can detect. ROYGBIV
Radio Waves
At one end of the E-M spectrum. Greatest Wavelength. Lowest Frequency.
Gamma Ray
At one end of the E-M spectrum. Shortest Wavelength. Greatest Frequency.
Radio Waves Source
Electronic Circuits
Radio Waves Detector
Aerial
Radio Waves Typical Uses
Communications, Radio, TV
Microwaves Source
Electronic Circuits
Microwaves Detector
Aerial
Microwaves Typical Uses
Communications Satellites
Infrared Sources
Electronic Devices
Warm Objects, Sun
Infrared Detectors
Electronic Detectors
Heat-Sensitive Papers
Black-Bulb Thermometer
Infrared Uses
Remote Controls
Detector in Security Lighting
Visible Light Sources
Sun
Electronic Devices
Visible Light Detectors
Eyes
Photographic Film
LDR
Visible Light Typical Uses
Seeing
Photography
Communication (Optical Fibres)
Ultraviolet Sources
Sun
Gas Discharge
Lamps
Ultraviolet Detector
Film
Causes Fluoresence in Some Objects (Money)
Ultraviolet Uses
Sun-Tan Lamp
Making Ions
Killing Bacteria
Making Vitamin D
X-Rays Sources
Very Fast Electrons Hitting a Metal Target
X-Rays Detector
Photographic Film
X-Rays Uses
Imaging Defects in Bones
Gamma Rays Sources
Radioactive Nuclei Decaying
Gamma Rays Detectors
Photographic FIlm
G-M Tube