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Robotics Worksheet: Line Follower Light Sensors

Robotics lesson 18: Light sensors and lines · Set 21 · 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.⬛ Why does a light sensor read a LOW number over a black line? (a) black is wet (b) black is hot (c) black soaks up light (d) black is loud
  2. 2.🔦 A light sensor reads 20 over black and 90 over white. A good threshold is halfway between them. What is it?
  3. 3.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 25. What is under the sensor? (a) the black line (b) the white floor
  4. 4.⬛ A reading below the threshold means the sensor is over … (a) the sky (b) water (c) white (d) black
  5. 5.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 45. What is under the sensor? (a) the black line (b) the white floor
  6. 6.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 60 and the right sensor reads 95. Which sensor is over the black line? (a) neither sensor (b) both sensors (c) the right sensor (d) the left sensor
  7. 7.🔦 A light sensor reads 30 over black and 60 over white. A good threshold is halfway between them. What is it?
  8. 8.⬛ The threshold of a light sensor is … (a) the battery size (b) the top speed (c) the wheel size (d) the black/white cut-off
  9. 9.🔦 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 black line (b) the white floor
  10. 10.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 13. What is under the sensor? (a) the white floor (b) the black line
  11. 11.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 22. What is under the sensor? (a) the white floor (b) the black line
  12. 12.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 15. What is under the sensor? (a) the black line (b) the white floor
  13. 13.🔦 A light sensor reads below 40 over a black line and above 40 over the white floor. It reads 19. What is under the sensor? (a) the black line (b) the white floor
  14. 14.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 70 and the right sensor reads 35. Which sensor is over the black line? (a) the left sensor (b) the right sensor (c) both sensors (d) neither sensor
  15. 15.🔦 A light sensor reads below 40 over a black line and above 40 over the white floor. It reads 45. What is under the sensor? (a) the black line (b) the white floor
  16. 16.🔦 A light sensor reads 10 over black and 60 over white. A good threshold is halfway between them. What is it?
  17. 17.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 20 and the right sensor reads 15. Which sensor is over the black line? (a) both sensors (b) the left sensor (c) the right sensor (d) neither sensor
  18. 18.🔦 A light sensor reads below 60 over a black line and above 60 over the white floor. It reads 41. What is under the sensor? (a) the black line (b) the white floor
  19. 19.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 44. What is under the sensor? (a) the black line (b) the white floor
  20. 20.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 75 and the right sensor reads 20. Which sensor is over the black line? (a) both sensors (b) the left sensor (c) the right sensor (d) neither sensor
  21. 21.⬛ In a two-sensor line follower, both sensors see white. Where is the line? (a) under the left sensor (b) under the right sensor (c) far behind it (d) between the two sensors
  22. 22.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 35 and the right sensor reads 20. Which sensor is over the black line? (a) both sensors (b) the right sensor (c) the left sensor (d) neither sensor
  23. 23.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 35 and the right sensor reads 35. Which sensor is over the black line? (a) neither sensor (b) the right sensor (c) both sensors (d) the left sensor
  24. 24.🔦 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 white floor (b) the black line
  25. 25.🔦 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
  26. 26.🔦 A light sensor reads 20 over black and 70 over white. A good threshold is halfway between them. What is it?
  27. 27.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 60 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 robot has a left and a right light sensor. Below 50 means black. The left sensor reads 80 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
  29. 29.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 70 and the right sensor reads 40. 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 30 over black and 70 over white. A good threshold is halfway between them. What is it?
  31. 31.🔦 A light sensor reads below 40 over a black line and above 40 over the white floor. It reads 16. 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 15 and the right sensor reads 15. Which sensor is over the black line? (a) neither sensor (b) the left sensor (c) both sensors (d) the right sensor
  33. 33.🔦 A light sensor reads 30 over black and 80 over white. A good threshold is halfway between them. What is it?
  34. 34.🔦 A light sensor reads 40 over black and 60 over white. A good threshold is halfway between them. What is it?
  35. 35.🔦 A light sensor reads 20 over black and 60 over white. A good threshold is halfway between them. What is it?
  36. 36.🔦 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) neither sensor (b) the left sensor (c) the right sensor (d) both sensors
  37. 37.🔦 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
  38. 38.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 35 and the right sensor reads 85. Which sensor is over the black line? (a) the left sensor (b) both sensors (c) neither sensor (d) the right sensor
  39. 39.🔦 A light sensor reads 40 over black and 70 over white. A good threshold is halfway between them. What is it?
  40. 40.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 10 and the right sensor reads 10. Which sensor is over the black line? (a) the right sensor (b) the left sensor (c) both sensors (d) neither sensor

Answer key

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

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