Topic 5- Light + Electromagnetic Spectrum Flashcards
What type of wave are em waves?
Transverse - particles oscillate perpendicular to the direction of travel of the wave. They travel at the same speed in a vacuum
What is the EM spectrum in terms of waves?
A continuous range of wavelengths, you can have a wave that behaves like a radio wave + microwave
What part of the EM spectrum can humans detect?
Only visible light
Describe the wavelength on the EM spectrum
Longest wavelength at top (radio) shortest wavelength at bottom (gamma).
Describe the frequency on the EM spectrum
Lowest frequency at top (radio) highest frequency at bottom (gamma)
Describe the energy on the EM spectrum
Lowest energy at top (radio) highest energy at bottom (gamma)
How are radio waves produced?
An alternating current or oscillations in electrical circuits is applied to transmitter which produces radio waves at same frequency as alternating current
How are radio waves detected?
A radio wave hits an aerial + causes an alternating current in the circuit as the same frequency as the radio waves
What are some uses of radio waves?
Radio, tv, communications
What are some uses + dangers of micro waves?
Cooking food, mobile phones . Internal heating of body cells
What are some uses and dangers of infrared waves?
Thermal imaging. Remote controls. Cooking food. Burns skin cells
What are some uses and dangers of visible light?
Vision, photography, lighting. Damage your retina
What are some uses and dangers of UV light?
Disinfecting water, detecting forged bank notes. Damages skin cells + eyes
What are some uses and dangers of X - rays?
Detection + treatment of cancer. Mutation of cells leading to cancer.
What can changes to atoms + nuclei do?
Generate waves of any frequency
Be caused by the absorption of waves of any frequency
What is the acronym for order of the EM spectrum?
Ruby Makes Indian Vindaloos Using Xtra Garlic
When a wave meets a boundary between two materials (a material interface) what happens?
Wave can either:
Be absorbed by second material- wave transfers every to materials energy stores
Be transmitted through second material - wave carries on travelling
Be reflected - Ray is sent back from material, happens on glass
What do all em waves transfer?
Transfer energy from source to an absorber. Eg when you wean yourself by electric heater, infrared waves transfer energy from the thermal energy store of heater(source) to your thermal energy store (absorber)
What’s the danger with high frequency em waves?
Higher the frequency, the more energy it transfers and so more dangerous it is
What can changes in atoms and nuclei do?
Generate radiations over a wide frequency range
What causes changes in atoms and nuclei?
Absorption of a range of radiations
