P1.2 - Refracting Telescope

Question 1

What is a converging/convex lens

Answer 1

Convex lenses are thicker at the middle. Rays of light that pass through the lens are brought closer together (they converge). A convex lens is a converging lens. When parallel rays of light pass through a convex lens the refracted rays converge at one point called the principal focus. The distance between the principal focus and the centre of the lens is called the focal length.

Question 2

How do refracting telescopes work

Answer 2

Using a convex/converging lens at the end of the telescope, which makes the light rays converge in the middle of the telescope where they are then magnified by an eyepiece lens at the end.

Question 3

Why does refraction occur

Answer 3

Light travels at different speeds in different materials. For example, light travels fast in the air, but when it hits glass, the waves travel more slowly making them refract towards the normal line.

Question 4

Explain refraction

Answer 4

Light travels in straight lines but when it hits a different material it can change directions. This is known as refraction.