Total internal reflection can occur as long as the angles made by the rays are greater than the critical angle. In glass the critical angle is around 42° and today we use very narrow fibres of glass to transmit pulses of light.
These are called optical fibres. They are used in telecommunications to transmit telephone conversations and data - including this web page to your computer! Whilst traditional copper wires can be used (and indeed are for the first 500 m or so from your phone) they cannot carry as much information and suffer from magnetic interference.
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