Physics
The mercury and sodium street lamps light up because of :

Electron absorption
Atomic absorption
Electron emission
Atomic emission

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Physics
In total internal reflection, the light travel from

Denser to rarer medium and it occurs with no loss of intensity
Rarer to denser medium and it occurs with loss of intensity
Denser to rarer medium and it occurs with loss of intensity
Rarer to denser medium and it occurs with no loss of intensity

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