LCD screens use polarizers because:

  1. they focus light
  2. they need sound waves
  3. they emit polarized sound
  4. liquid crystals control the light by rotating its plane of polarization
Answer

D) liquid crystals control the light by rotating its plane of polarization

Pixels are switched between crossed polarizers. SLO P-11-D-17 · Understanding

Physics MCQ · More Polarization MCQs · Practise