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Robotics Worksheet: Line Follower Light Sensors

Robotics lesson 18: Light sensors and lines · Set 708 · 40 questions
TalentJR

Robot tip (Below the threshold is black): Reading below the threshold → black; above → white. Threshold = (black reading + white reading) ÷ 2. Two sensors: the one that reads black is over the line; both white → the line is between them.

NameDateTime takenScore ___ / 40
  1. 1.🔦 A light sensor reads below 40 over a black line and above 40 over the white floor. It reads 34. What is under the sensor? (a) the white floor (b) the black line
  2. 2.⬛ The threshold of a light sensor is … (a) the top speed (b) the wheel size (c) the black/white cut-off (d) the battery size
  3. 3.⬛ Why does a light sensor read a LOW number over a black line? (a) black soaks up light (b) black is hot (c) black is loud (d) black is wet
  4. 4.🔦 A light sensor reads 40 over black and 70 over white. A good threshold is halfway between them. What is it?
  5. 5.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 56. What is under the sensor? (a) the black line (b) the white floor
  6. 6.🔦 A light sensor reads below 60 over a black line and above 60 over the white floor. It reads 55. What is under the sensor? (a) the black line (b) the white floor
  7. 7.⬛ In a two-sensor line follower, both sensors see white. Where is the line? (a) under the right sensor (b) between the two sensors (c) far behind it (d) under the left sensor
  8. 8.🔦 A light sensor reads 30 over black and 80 over white. A good threshold is halfway between them. What is it?
  9. 9.⬛ A reading below the threshold means the sensor is over … (a) water (b) the sky (c) white (d) black
  10. 10.🔦 A light sensor reads below 40 over a black line and above 40 over the white floor. It reads 29. What is under the sensor? (a) the white floor (b) the black line
  11. 11.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 15 and the right sensor reads 20. Which sensor is over the black line? (a) the right sensor (b) the left sensor (c) both sensors (d) neither sensor
  12. 12.🔦 A light sensor reads 30 over black and 60 over white. A good threshold is halfway between them. What is it?
  13. 13.🔦 A light sensor reads 40 over black and 60 over white. A good threshold is halfway between them. What is it?
  14. 14.🔦 A light sensor reads below 60 over a black line and above 60 over the white floor. It reads 39. What is under the sensor? (a) the black line (b) the white floor
  15. 15.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 15 and the right sensor reads 60. Which sensor is over the black line? (a) the right sensor (b) the left sensor (c) neither sensor (d) both sensors
  16. 16.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 65 and the right sensor reads 90. Which sensor is over the black line? (a) neither sensor (b) the right sensor (c) both sensors (d) the left sensor
  17. 17.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 42. What is under the sensor? (a) the black line (b) the white floor
  18. 18.🔦 A light sensor reads 20 over black and 60 over white. A good threshold is halfway between them. What is it?
  19. 19.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 25 and the right sensor reads 90. Which sensor is over the black line? (a) neither sensor (b) both sensors (c) the left sensor (d) the right sensor
  20. 20.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 25. What is under the sensor? (a) the white floor (b) the black line
  21. 21.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 26. What is under the sensor? (a) the white floor (b) the black line
  22. 22.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 17. What is under the sensor? (a) the white floor (b) the black line
  23. 23.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 15 and the right sensor reads 25. Which sensor is over the black line? (a) the left sensor (b) neither sensor (c) both sensors (d) the right sensor
  24. 24.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 35. What is under the sensor? (a) the white floor (b) the black line
  25. 25.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 20 and the right sensor reads 80. Which sensor is over the black line? (a) neither sensor (b) the left sensor (c) both sensors (d) the right sensor
  26. 26.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 60. What is under the sensor? (a) the black line (b) the white floor
  27. 27.🔦 A light sensor reads 20 over black and 90 over white. A good threshold is halfway between them. What is it?
  28. 28.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 80 and the right sensor reads 60. Which sensor is over the black line? (a) the right sensor (b) the left sensor (c) neither sensor (d) both sensors
  29. 29.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 35 and the right sensor reads 60. Which sensor is over the black line? (a) the right sensor (b) neither sensor (c) both sensors (d) the left sensor
  30. 30.🔦 A light sensor reads 10 over black and 70 over white. A good threshold is halfway between them. What is it?
  31. 31.🔦 A light sensor reads below 60 over a black line and above 60 over the white floor. It reads 64. What is under the sensor? (a) the white floor (b) the black line
  32. 32.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 25 and the right sensor reads 95. Which sensor is over the black line? (a) the left sensor (b) neither sensor (c) the right sensor (d) both sensors
  33. 33.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 36. What is under the sensor? (a) the black line (b) the white floor
  34. 34.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 10 and the right sensor reads 70. Which sensor is over the black line? (a) neither sensor (b) the left sensor (c) the right sensor (d) both sensors
  35. 35.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 71. What is under the sensor? (a) the black line (b) the white floor
  36. 36.🔦 A light sensor reads 20 over black and 70 over white. A good threshold is halfway between them. What is it?
  37. 37.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 40 and the right sensor reads 75. Which sensor is over the black line? (a) both sensors (b) the right sensor (c) the left sensor (d) neither sensor
  38. 38.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 57. What is under the sensor? (a) the white floor (b) the black line
  39. 39.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 95 and the right sensor reads 85. Which sensor is over the black line? (a) both sensors (b) the left sensor (c) the right sensor (d) neither sensor
  40. 40.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 55. What is under the sensor? (a) the white floor (b) the black line

Answer key

  1. the black line
  2. the black/white cut-off
  3. black soaks up light
  4. 55
  5. the white floor
  6. the black line
  7. between the two sensors
  8. 55
  9. black
  10. the black line
  11. both sensors
  12. 45
  13. 50
  14. the black line
  15. the left sensor
  16. neither sensor
  17. the black line
  18. 40
  19. the left sensor
  20. the black line
  21. the black line
  22. the black line
  23. both sensors
  24. the black line
  25. the left sensor
  26. the white floor
  27. 55
  28. neither sensor
  29. the left sensor
  30. 40
  31. the white floor
  32. the left sensor
  33. the white floor
  34. the left sensor
  35. the white floor
  36. 45
  37. the left sensor
  38. the white floor
  39. neither sensor
  40. the white floor

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