criss cross word

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Across
  1. 1. /the black center of the eye
  2. 4. /highest point of wave
  3. 5. /repetition of wave, measured in hertz
  4. 7. /measures power in electrical systems
  5. 9. /thin elongated objects or cylindrical structure
  6. 10. /illuminating objects, electromagnetic radiation
  7. 12. /innermost layer of the eye, crucial for vision
  8. 13. /invisible radiation beyond red light, detected as heat
  9. 16. /takes in another substance or light
  10. 18. /electromagnetic radiation beyond violet light
  11. 19. /refracts light and creates rainbows like effects
Down
  1. 2. /transparent optical element that refracts light
  2. 3. /the darkness crated by shelter
  3. 4. /a lens that curves inwards
  4. 6. /colored substance that reflects certain wavelengths of light
  5. 8. /long narrow container or low point
  6. 11. /allows light to pass through
  7. 14. /the unit of energy in the SI measuring heat and work
  8. 15. /central, darkest part of a shadow where light is completely blocked
  9. 17. /sending signals through mediums, such as air