or less in diameter). [P6.2]
is: a very thin strand of glass (usually of the order of or less in diameter). [P6.2]
is used: to confine light rays at a sufficiently small angle to the axis of the fibre, by total internal reflections and thereby to convey these rays up to many kilometres with little power loss. Usually many individual fibres are bundled together to form a cable. [P6.2]
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