The angle of refraction (r) of a ray of white light from air through a triangular glass prism of refractive index 1.5 is 29.0°. Calculate the angle…

Comparative advantage: countries should specialize in goods they produce at lowest opportunity cost, even if another country is better at producing everything (absolute advantage).

Example: If Nigeria can produce oil more efficiently relative to textiles than Ghana can, Nigeria should specialize in oil and trade for Ghanas textiles, even if Nigeria could produce both more efficiently.

This principle justifies international trade – specialization increases total world output. All countries benefit by trading according to comparative advantage. Basis for free trade arguments.