Electromagnetic waves
Spectrum,
wavelength and frequency, variations, ROYGBIV, emission –
everything emits, depends on temperature, composition
effects,
selectivity wavelength dependence;
transmission, transparency, absorbed and re-emitted, affects
speed of transmission, controls color of transparent objects – absorbs
all
colors except the few transmitted so it appears the color of the
transmitted few ;
absorption, opacity, energy excites the molecules, causing
collisions
and conversion of energy to heat, black absorbs all and gains most heat;
reflection, white objects reflect all wavelengths, gives color,
only reflect certain wavelengths, if those wavelengths not available –
not that color;
scattering, energy absorbed and re-emitted in all directions,
size of
particle affects which wavelengths are scattered
Atmospheric effects,
blue sky, red sunsets, clouds
Sketch a typical transverse wave and label: wavelength and
amplitude. Explain the relationships between wavelength,
frequency, period and speed. How is this different from a
longitudinal wave?
Compare and contrast sound waves and light waves.
Explain the Doppler effect. Give an example of how it can be used
to gain practical information. (tornadoes, stars…)
Sketch the electromagnetic spectrum and label the relative positions
of: radio waves, microwaves, infra-red waves, visible light, UV
waves, and x-rays. Explain how the temperature of a source
controls the amount and wavelengths of electromagnetic radiation
emitted.
Compare and contrast: emission, transmission, absorption,
reflection, and scattering. Which of these affect an object’s
color and how do they cause this effect?
Why is the sky blue during the day but reddish at sunset? What
does a hazy white/gray sky indicate?
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