Questions

Between glass and water, glass is considered a denser medium and water is a rarer medium. Why?

Differentiate: color blindness and night blindness

Differentiate: shortsightedness and longsightedness

Differentiate: near point of the eye and far point of the eye

Differentiate: concave lens and convex lens

Differentiate: reflection of light and total internal reflection of light.

How many terms must be taken of: the series $\rm 9 + 3 + 1 + \dots $to make the sum $\rm \frac{121}{9}$?

How many terms must be taken of: the series $3 + 6+12 + \dots $ to make the sum 1533?

How many terms must be taken of: the series $\rm 64 + 96 + 144 + \dots $, to make the sum 1330?

How many terms must be taken of: the series $\rm 4 + 8 + 16 +\dots $ to make the sum 508?