Flashcards in The Electromagnetic Spectrum Deck (21):
What is the EM spectrum?
Radio waves - longest wavelength, lowest frequency
Gamma rays - shortest wavelength, highest frequency
What was Herschel's experiment?
Put filters on telescope, noticed that different coloured filters heated telescope to different extents. Used a prism to split sunlight into spectrum, put two thermometers on either side of the spectrum. Found that temp rose with colour change from violet to red. Measured temp just beyond red of spectrum, where there was no visible light, found that this gave highest temp, called it infrared.
Describe Ritter's experiment
Used silver chloride, which turns black when exposed to light. Turned black faster in violet light than red light, but turned black fastest when exposed to invisible Rays beyond violet. Ultraviolet rays
Are electromagnetic waves transverse or longitudinal?
Transverse, travel at same speed in a vacuum.
How does the danger of electromagnetic waves increase?
Higher frequency = more dangerous
What are the harmful effects of microwaves?
Internal heating of body cells
What are the harmful effects of infrared?
What are the harmful effects of ultraviolet?
Damage to surface cells & eyes, leading to skin cancer & eye conditions
What are the harmful effects of X-rays and gamma rays?
Mutation or damage to cells in body
What are the uses of radio waves?
Broadcasting, communications, satellite transmissions
What are the uses of microwaves?
Cooking,communications, satellite transmissions
What are the uses of infrared?
Cooking, thermal imaging, short range communications, optical fibres, television remote controls, security systems
What are the uses of visible light?
Vision, photography, illumination
What are the uses of ultraviolet?
Security marking, fluorescent lamps,mete ting forged bank notes, disinfecting water
What are the uses of X-rays?
Observing internal structure of objects, airport security scanners, medical X-rays
What are the uses of gamma rays?
Sterilising food and medical equipment, detection of cancer & its treatment
How are ionising radiations emitted?
All the time by radioactive sources
What does ionising radiation emit?
Alpha and beta particles and gamma rays, they transfer energy
What is ionising radiation?
Radiation or certain types of high-energy particles that can cause atoms to become electrically charged (to become ions)
What are ionising radiations emitted by?
Radioactive sources all the time