Knock out the false photon claims

Exercise and reference answers

Questions

1. Question

   Three of these statements about the photoelectric effect are false.

   Choices

   1. Explanation

      Intensity raises the count of electrons, not their energy

      Item

      Brighter light gives faster electrons

   2. Item

      Maximum kinetic energy tracks frequency

      Correct

      Yes

   3. Explanation

      Below the threshold frequency nothing is emitted at all

      Item

      Any frequency ejects electrons eventually

   4. Explanation

      These are the features wave theory could not explain

      Item

      Classical wave theory predicted this

2. Question

   Three of these claims about de Broglie waves are wrong.

   Choices

   1. Explanation

      Every moving particle carries wave properties

      Item

      Only photons carry a wavelength

   2. Explanation

      Wavelength falls as momentum rises

      Item

      A faster particle has a longer wave

   3. Item

      Wavelength is h divided by momentum

      Correct

      Yes

   4. Explanation

      For a 1 kg ball at 1 m/s the wavelength is about 10^-34 m

      Item

      A 1 kg ball shows a measurable wave

Instructions

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

Explanation