W2 Refraction and Lens Power

What is dispersion?

White light can be split into its components by a transparent refracting medium such as a prism or lens

What makes a lens thin?

The higher the refractive index of a transparent material used to manufacture a lens, the thinner the lens will become

What is the structure of a positive lens?

Thickest at the lens centre and thinnest at the lens edge

What are positive lens used to treat?

Hyperopia and presbyopia

What are features of a positive biconvex lens?

Both front and back surface have positive power

What are features of a positive plano convex lens?

Front has positive power, back surface has no power (Plano)

What are features of a positive convex meniscus lens?

Front surface has positive power back surface has negative power

What’s the structure of a positive/converging lens?

What does a negative lens (diverging or concave) look like?

What are features of negative lens?

Thickest at lens edge, thinnest at centre, corrects myopia

What are features of negative biconcave lens?

Front and back surface both have negative power

What are features of negative Plano concave lens?

Front surface has no power (Plano) and back surface has negative power

What are features of negative concave meniscus lens?

Front surface has positive power back surface has negative power