How does heat travel through space?
By infrared waves
What emits and absorbs thermal radiation?
All bodies
What is thermal (infrared) radiation?
The transfer of energy by electromagnetic waves
What is a thermograph?
The images taken using infrared radiation
If an object’s temperature is higher, what will happen to the infrared radiation it’s emitting?
Higher temperature -> more infrared radiation emitted in a given time
What happens as a filament lamp warms up?
- doesn’t glow, emits infrared
- warms up glows dull red -> emitting visible spectrum
- orange-red
- yellow-white as filament gets hotter
What does the intensity of radiation at a certain wavelength depend on?
Temperature
What happens as temperature and radiation increases?
Radiation increases at every wavelength and the peak moves to a shorter wavelength (high frequency)
What happens to radiation as temperature increases?
If temperature increases, intensity of radiation increases at every wavelength so peak moves to a shorter wavelength
What does the temperature of the earth depend on?
- The rate that light and infrared radiation are absorbed by the atmosphere/surface or are reflected back into space
- The rate at which the earth emits radiation from its surface and atmosphere
How do loudspeakers work?
- ac current is passed through coil which is attached to paper cone
- current causes force on coil so paper cone moves
- current reverses and force acts on cone in opposite direction
- cone vibrates
