Knock out the false light claims

Exercise and reference answers

Questions

1. Question

   Three of these claims about the speed of light are false.

   Choices

   1. Item

      Its speed is the same in all frames

      Correct

      Yes

   2. Explanation

      A source's motion is never added to the speed of the light it emits.

      Item

      A moving lamp adds speed to its light

   3. Explanation

      The interferometer showed no fringe shift, so no ether carried the waves.

      Item

      Light needs an ether to travel

   4. Explanation

      A ball thrown near light speed is still seen moving slower than light.

      Item

      Velocities simply add at any speed

2. Question

   Three of these claims about two flashes on a moving rail car are false.

   Choices

   1. Explanation

      The rider meets the flash from the leading lamp first.

      Item

      Both observers see them together

   2. Explanation

      Light holds one speed no matter how its lamp is moving.

      Item

      Light from the front travels faster

   3. Item

      Simultaneity depends on the frame

      Correct

      Yes

   4. Explanation

      Neither frame is privileged, so both readings are equally valid.

      Item

      Only one frame is the correct one

Instructions

Tap each claim about light and moving frames you can prove false. The true one stays standing.

Explanation