Knock out the false optics claims

Exercise and reference answers

Questions

1. Question

   Three of these statements about total internal reflection are false.

   Choices

   1. Explanation

      Going into a denser medium the ray always refracts inward

      Item

      It needs light going rarer to denser

   2. Explanation

      The angle of incidence must go past the critical angle

      Item

      It fires below the critical angle

   3. Item

      It needs light going denser to rarer

      Correct

      Yes

   4. Explanation

      Below the critical angle the ray simply refracts across

      Item

      It happens at any angle at all

2. Question

   Three of these statements about a plane mirror image are false.

   Choices

   1. Explanation

      A plane mirror image is virtual, so no screen can catch it

      Item

      The image can be caught on a screen

   2. Item

      It sits as far behind as object in front

      Correct

      Yes

   3. Explanation

      A plane mirror gives an image the same size as the object

      Item

      The image is smaller than the object

   4. Explanation

      A plane mirror image is erect, with left and right swapped

      Item

      The image is turned upside down

Instructions

Three lines in each round are wrong. Tap those three and leave the one that stands.

Explanation