Question

Give reasons for the following
Ordinary key chain laser light should not be directly viewed.

Answer 1

Ordinary key chain lasers should not be directly viewed because laser is a light source that can be dangerous to people exposed to it. These are hazardous to a persons's eyesight. The coherence and lower divergence of these laser light means that it can be focussed by the eye into an extremely small spot on retina, resulting in localised burning and permanent damage in seconds.