Lenses in contact

Exercise and reference answers

Questions

1. Question

   For thin lenses in contact, the powers

   Choices

   1. add
   2. multiply
   3. subtract

   Correct choice

   add

2. Question

   For thin lenses in contact, the reciprocals of focal length

   Choices

   1. multiply
   2. add
   3. cancel

   Correct choice

   add

3. Question

   The focal length of a mirror is about

   Choices

   1. twice the radius
   2. equal to R
   3. half the radius of curvature

   Correct choice

   half the radius of curvature

4. Question

   Dispersion is

   Choices

   1. splitting light into its colours
   2. bending at a surface
   3. reflection inside a medium

   Correct choice

   splitting light into its colours

Explanation