Question

what is total internal reflection ​

Answer 1

Explanation:

That makes water to air surface in a fish tank

look like perfectly silver mirror

Answer 2

Explanation:

total internal reflection.

When light is incident upon a medium of lesser index of refraction, the ray is bent away from the normal, so the exit angle is greater than the incident angle. Such reflection is commonly called "internal reflection". The exit angle will then approach 90° for some critical incident angle θc , and for incident angles greater than the critical angle there will be total internal reflection.