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Robotics Worksheet: Line Follower Light Sensors

Robotics lesson 18: Light sensors and lines · Set 125 · 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 30 over black and 90 over white. A good threshold is halfway between them. What is it?
  2. 2.⬛ In a two-sensor line follower, both sensors see white. Where is the line? (a) under the left sensor (b) far behind it (c) between the two sensors (d) under the right sensor
  3. 3.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 30 and the right sensor reads 85. Which sensor is over the black line? (a) neither sensor (b) the left sensor (c) both sensors (d) the right sensor
  4. 4.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 21. What is under the sensor? (a) the white floor (b) the black line
  5. 5.🔦 A light sensor reads 40 over black and 60 over white. A good threshold is halfway between them. What is it?
  6. 6.🔦 A light sensor reads 30 over black and 80 over white. A good threshold is halfway between them. What is it?
  7. 7.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 35 and the right sensor reads 70. Which sensor is over the black line? (a) the right sensor (b) both sensors (c) the left sensor (d) neither sensor
  8. 8.🔦 A light sensor reads 10 over black and 90 over white. A good threshold is halfway between them. What is it?
  9. 9.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 95 and the right sensor reads 25. Which sensor is over the black line? (a) the left sensor (b) both sensors (c) the right sensor (d) neither sensor
  10. 10.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 75 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
  11. 11.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 65 and the right sensor reads 60. Which sensor is over the black line? (a) the right sensor (b) both sensors (c) neither sensor (d) the left sensor
  12. 12.⬛ The threshold of a light sensor is … (a) the wheel size (b) the top speed (c) the battery size (d) the black/white cut-off
  13. 13.🔦 A light sensor reads 10 over black and 60 over white. A good threshold is halfway between them. What is it?
  14. 14.🔦 A light sensor reads 20 over black and 80 over white. A good threshold is halfway between them. What is it?
  15. 15.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 66. What is under the sensor? (a) the black line (b) the white floor
  16. 16.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 70 and the right sensor reads 80. Which sensor is over the black line? (a) the right sensor (b) the left sensor (c) neither sensor (d) both sensors
  17. 17.🔦 A light sensor reads below 60 over a black line and above 60 over the white floor. It reads 67. What is under the sensor? (a) the white floor (b) the black line
  18. 18.⬛ A reading below the threshold means the sensor is over … (a) the sky (b) water (c) white (d) black
  19. 19.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 10 and the right sensor reads 60. 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 60 over a black line and above 60 over the white floor. It reads 72. What is under the sensor? (a) the black line (b) the white floor
  21. 21.🔦 A light sensor reads 40 over black and 70 over white. A good threshold is halfway between them. What is it?
  22. 22.🔦 A light sensor reads 20 over black and 70 over white. A good threshold is halfway between them. What is it?
  23. 23.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 60 and the right sensor reads 10. Which sensor is over the black line? (a) the left sensor (b) the right sensor (c) both sensors (d) neither sensor
  24. 24.🔦 A light sensor reads 30 over black and 60 over white. A good threshold is halfway between them. What is it?
  25. 25.🔦 A light sensor reads 40 over black and 90 over white. A good threshold is halfway between them. What is it?
  26. 26.🔦 A light sensor reads below 40 over a black line and above 40 over the white floor. It reads 26. What is under the sensor? (a) the white floor (b) the black line
  27. 27.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 80 and the right sensor reads 70. Which sensor is over the black line? (a) neither sensor (b) the left sensor (c) both sensors (d) the right sensor
  28. 28.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 43. What is under the sensor? (a) the black line (b) the white floor
  29. 29.🔦 A light sensor reads below 40 over a black line and above 40 over the white floor. It reads 37. What is under the sensor? (a) the black line (b) the white floor
  30. 30.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 10. What is under the sensor? (a) the black line (b) the white floor
  31. 31.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 85 and the right sensor reads 80. Which sensor is over the black line? (a) the right sensor (b) the left sensor (c) both sensors (d) neither sensor
  32. 32.🔦 A light sensor reads below 60 over a black line and above 60 over the white floor. It reads 56. What is under the sensor? (a) the black line (b) the white floor
  33. 33.🔦 A light sensor reads 10 over black and 80 over white. A good threshold is halfway between them. What is it?
  34. 34.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 60 and the right sensor reads 80. Which sensor is over the black line? (a) the left sensor (b) the right sensor (c) neither sensor (d) both sensors
  35. 35.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 49. What is under the sensor? (a) the black line (b) the white floor
  36. 36.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 25 and the right sensor reads 10. Which sensor is over the black line? (a) both sensors (b) the right sensor (c) the left sensor (d) neither sensor
  37. 37.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 90 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
  38. 38.⬛ Why does a light sensor read a LOW number over a black line? (a) black is loud (b) black is hot (c) black is wet (d) black soaks up light
  39. 39.🔦 A light sensor reads below 40 over a black line and above 40 over the white floor. It reads 25. What is under the sensor? (a) the black line (b) the white floor
  40. 40.🔦 A light sensor reads below 60 over a black line and above 60 over the white floor. It reads 68. What is under the sensor? (a) the black line (b) the white floor

Answer key

  1. 60
  2. between the two sensors
  3. the left sensor
  4. the black line
  5. 50
  6. 55
  7. the left sensor
  8. 50
  9. the right sensor
  10. neither sensor
  11. neither sensor
  12. the black/white cut-off
  13. 35
  14. 50
  15. the white floor
  16. neither sensor
  17. the white floor
  18. black
  19. the left sensor
  20. the white floor
  21. 55
  22. 45
  23. the right sensor
  24. 45
  25. 65
  26. the black line
  27. neither sensor
  28. the white floor
  29. the black line
  30. the black line
  31. neither sensor
  32. the black line
  33. 45
  34. neither sensor
  35. the white floor
  36. both sensors
  37. neither sensor
  38. black soaks up light
  39. the black line
  40. the white floor

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