Interesting question. I'd take a guess that it could be either mirrors and light travelling in straight lines and being reflected, or optical fibres to achieve a perhaps similar result.
Answer:
| w | = w√ ( sin^2 ∝ + cos^2∝ ) shows that w is independent of time hence it is constant
Explanation:
prove that the magnitude of <em>w</em> is constant
attached below is a detailed solution of the question
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