Lenses

Question 1

Describe a convex lens

Answer 1

Thicker at the centre than the edges

Question 2

Describe a parallel ray of light passing through a convex lens

Answer 2

• central ray passes through lens without being refracted
  = ray is passing directly along the normal
• all other rays refract and are focused on a point (principle focus)

Question 3

Define a focal lens

Answer 3

Distance from the lens to the principal focus

Question 4

Describe a concave lens

Answer 4

Thicker at the edges than the centre

Question 5

Effects of concave lens

Answer 5

Make light rays spread out
= light rays diverge