Spot the one that does not fit

Exercise and reference answers

Questions

1. Items

   1. Mirror
   2. Convex lens
   3. Concave lens
   4. Dioptre

   Odd item

   Mirror

2. Items

   1. Converging
   2. Thick middle
   3. Positive power
   4. Thick edges

   Odd item

   Thick edges

3. Items

   1. 1.33
   2. Water
   3. Refractive index
   4. Focal length

   Odd item

   Focal length

4. Items

   1. Dioptre
   2. Power
   3. One metre
   4. Kilogram

   Odd item

   Kilogram

Instructions

Tap the item that does not belong with the rest.

Explanation