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Robotics Worksheet: Line Follower Light Sensors

Robotics lesson 18: Light sensors and lines · Set 323 · 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 10 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) between the two sensors (b) far behind it (c) under the right sensor (d) under the left sensor
  3. 3.⬛ The threshold of a light sensor is … (a) the battery size (b) the black/white cut-off (c) the wheel size (d) the top speed
  4. 4.🔦 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 white floor (b) the black line
  5. 5.🔦 A light sensor reads below 60 over a black line and above 60 over the white floor. It reads 85. What is under the sensor? (a) the white floor (b) the black line
  6. 6.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 37. What is under the sensor? (a) the black line (b) the white floor
  7. 7.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 12. What is under the sensor? (a) the white floor (b) the black line
  8. 8.🔦 A light sensor reads 10 over black and 60 over white. A good threshold is halfway between them. What is it?
  9. 9.🔦 A light sensor reads 30 over black and 90 over white. A good threshold is halfway between them. What is it?
  10. 10.🔦 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
  11. 11.🔦 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
  12. 12.🔦 A light sensor reads 20 over black and 80 over white. A good threshold is halfway between them. What is it?
  13. 13.⬛ A reading below the threshold means the sensor is over … (a) white (b) the sky (c) water (d) black
  14. 14.🔦 A light sensor reads 10 over black and 80 over white. A good threshold is halfway between them. What is it?
  15. 15.🔦 A light sensor reads 30 over black and 60 over white. A good threshold is halfway between them. What is it?
  16. 16.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 43. What is under the sensor? (a) the white floor (b) the black line
  17. 17.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 39. What is under the sensor? (a) the black line (b) the white floor
  18. 18.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 60 and the right sensor reads 75. Which sensor is over the black line? (a) the right sensor (b) the left sensor (c) both sensors (d) neither sensor
  19. 19.🔦 A light sensor reads 40 over black and 60 over white. A good threshold is halfway between them. What is it?
  20. 20.🔦 A light sensor reads below 40 over a black line and above 40 over the white floor. It reads 28. What is under the sensor? (a) the black line (b) the white floor
  21. 21.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 39. What is under the sensor? (a) the black line (b) the white floor
  22. 22.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 20 and the right sensor reads 35. Which sensor is over the black line? (a) the left sensor (b) both sensors (c) neither sensor (d) the right sensor
  23. 23.🔦 A light sensor reads 40 over black and 70 over white. A good threshold is halfway between them. What is it?
  24. 24.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 35 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
  25. 25.⬛ Why does a light sensor read a LOW number over a black line? (a) black is loud (b) black is wet (c) black soaks up light (d) black is hot
  26. 26.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 40 and the right sensor reads 70. Which sensor is over the black line? (a) the right sensor (b) neither sensor (c) the left sensor (d) both sensors
  27. 27.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 40. What is under the sensor? (a) the black line (b) the white floor
  28. 28.🔦 A light sensor reads 20 over black and 70 over white. A good threshold is halfway between them. What is it?
  29. 29.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 60 and the right sensor reads 25. Which sensor is over the black line? (a) both sensors (b) neither sensor (c) the left sensor (d) the right sensor
  30. 30.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 95 and the right sensor reads 40. Which sensor is over the black line? (a) neither sensor (b) the right sensor (c) the left sensor (d) both sensors
  31. 31.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 16. What is under the sensor? (a) the white floor (b) the black line
  32. 32.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 59. What is under the sensor? (a) the black line (b) the white floor
  33. 33.🔦 A light sensor reads below 60 over a black line and above 60 over the white floor. It reads 69. What is under the sensor? (a) the white floor (b) the black line
  34. 34.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 30 and the right sensor reads 60. Which sensor is over the black line? (a) both sensors (b) the left sensor (c) neither sensor (d) the right sensor
  35. 35.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 80 and the right sensor reads 30. Which sensor is over the black line? (a) the right sensor (b) neither sensor (c) both sensors (d) the left sensor
  36. 36.🔦 A light sensor reads below 60 over a black line and above 60 over the white floor. It reads 38. What is under the sensor? (a) the white floor (b) the black line
  37. 37.🔦 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) neither sensor (b) both sensors (c) the left sensor (d) the right sensor
  38. 38.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 40 and the right sensor reads 35. Which sensor is over the black line? (a) the right sensor (b) the left sensor (c) both sensors (d) neither sensor
  39. 39.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 75 and the right sensor reads 30. Which sensor is over the black line? (a) neither sensor (b) the right sensor (c) both sensors (d) the left sensor
  40. 40.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 45. What is under the sensor? (a) the black line (b) the white floor

Answer key

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

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