Question

which property of the coating on fiber - optic strands makes light visible only at the ends of the strands?
reflectivity
absorbency
transparency
translucency

Explanation:

Fiber - optic strands work based on the principle of total internal reflection. The coating on the fiber - optic strands has high reflectivity. This high reflectivity ensures that the light that enters the fiber - optic strand is reflected back into the core of the strand (due to the difference in refractive indices between the core and the coating) and travels along the length of the strand, so that the light is only visible at the ends of the strands. Absorbency would absorb the light, which is not what we want in fiber - optics. Transparency would allow light to pass through the coating and be visible along the length, and translucency would scatter the light, also making it visible along the length. So the property is reflectivity.

Answer:

reflectivity