The after glow from some clock faces is caused by atoms
1) being excited,
2) vibrating at frequencies greater than a million billion times per second,
3) remaining for some time in a state of excitation before de-exciting,
and materials exhibiting this property are called
4) fluorescent.
5) phosphorescent.
6) incandescent.
7) luminescent.
Question 2
A spectrum of colors seen in gasoline on a wet street is primarily a result of
1) interference,
2) polarization,
3) refraction,
4) scattering,
5) diffraction,
where
6) the light reaching the eye is polarized by double reflection.
7) only the higher frequencies of light resonate with the gasoline and H2O molecules.
8) the thin film of gasoline spreads the light out into its component colors.
9) light reflecting from the gasoline surface interferes with light reflecting from the water surface.
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