Waves And The EM Spectrum Flashcards
What happens towards the gamma rays end of spectrum
- more energy transferred
- short wavelength
- high frequency
What are the same for all electromagnetic waves
- are all transverse
- travel at the speed of light in a vacuum (3x10^8 m/s)
- travel at the same speed through the same material
How did Herschel make observations of the sun
Put a coloured filter over a telescope to try and make it safer
What did Herschel notice
Different coloured filters heat up by different amounts
What did Herschel do when he observed different coloured filters heat by different amounts, and what did he observe
He put a thermometer in the different colours by using a prism to break up the visible light. The temperature rose as as he moved from violet to red. He measured the temperature where there was no visible light at the red end of the spectrum
What did Herschel discover
Discovered that the temperature was highest at the red end of the spectrum. He discovered infrared (beyond red)
What did Ritter discover
He discovered ultraviolet when he tried to find invisible rays at the violet end of the spectrum
What did Ritter use and what did he see
He used silver chloride; which turns black when exposed to light. Happened fastest when exposed to invisible rays at the violet end
What is there towards the radio waves end of the spectrum
- less energy transferred
- long wavelength
- low frequency
What gives a tan but can cause cancer in cells
Ultraviolet
What is used to sterilise surgical instruments
Gamma rays
What is used to make toast
Infrared
What is used to change channels in a remote
Infrared
What is used to send information to and from satellites
Microwaves
How do microwaves heat food
The water molecules in the food absorb the microwave radiation and gain heat energy