Robotics Worksheet: Line Follower Light Sensors

Robotics lesson 18: Light sensors and lines · Set 531 · 40 questions

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.

1. 1.⬛ The threshold of a light sensor is … (a) the top speed (b) the black/white cut-off (c) the wheel size (d) the battery size
2. 2.🔦 A light sensor reads 40 over black and 60 over white. A good threshold is halfway between them. What is it?
3. 3.⬛ A reading below the threshold means the sensor is over … (a) water (b) the sky (c) black (d) white
4. 4.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 63. What is under the sensor? (a) the white floor (b) the black line
5. 5.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 80 and the right sensor reads 95. Which sensor is over the black line? (a) the left sensor (b) neither sensor (c) both sensors (d) the right sensor
6. 6.🔦 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
7. 7.🔦 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) both sensors (b) the right sensor (c) the left sensor (d) neither sensor
8. 8.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 65 and the right sensor reads 35. Which sensor is over the black line? (a) the left sensor (b) neither sensor (c) the right sensor (d) both sensors
9. 9.🔦 A light sensor reads below 60 over a black line and above 60 over the white floor. It reads 35. What is under the sensor? (a) the black line (b) the white floor
10. 10.⬛ Why does a light sensor read a LOW number over a black line? (a) black is hot (b) black is loud (c) black is wet (d) black soaks up light
11. 11.🔦 A light sensor reads below 40 over a black line and above 40 over the white floor. It reads 59. What is under the sensor? (a) the white floor (b) the black line
12. 12.🔦 A light sensor reads 40 over black and 90 over white. A good threshold is halfway between them. What is it?
13. 13.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 30 and the right sensor reads 40. Which sensor is over the black line? (a) the left sensor (b) the right sensor (c) neither sensor (d) both sensors
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 below 40 over a black line and above 40 over the white floor. It reads 27. 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) neither sensor (b) the right sensor (c) both sensors (d) the left sensor
17. 17.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 30 and the right sensor reads 70. Which sensor is over the black line? (a) the left sensor (b) the right sensor (c) both sensors (d) neither sensor
18. 18.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 85 and the right sensor reads 20. Which sensor is over the black line? (a) neither sensor (b) both sensors (c) the right sensor (d) the left sensor
19. 19.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 31. What is under the sensor? (a) the white floor (b) the black line
20. 20.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 36. What is under the sensor? (a) the white floor (b) the black line
21. 21.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 70 and the right sensor reads 90. Which sensor is over the black line? (a) the right sensor (b) both sensors (c) the left sensor (d) neither sensor
22. 22.⬛ In a two-sensor line follower, both sensors see white. Where is the line? (a) under the right sensor (b) under the left sensor (c) between the two sensors (d) far behind it
23. 23.🔦 A light sensor reads 20 over black and 60 over white. A good threshold is halfway between them. What is it?
24. 24.🔦 A light sensor reads below 40 over a black line and above 40 over the white floor. It reads 63. 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 85 and the right sensor reads 90. Which sensor is over the black line? (a) neither sensor (b) both sensors (c) the right sensor (d) the left sensor
26. 26.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 68. 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 40 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
28. 28.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 38. What is under the sensor? (a) the black line (b) the white floor
29. 29.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 40 and the right sensor reads 65. Which sensor is over the black line? (a) the right sensor (b) both sensors (c) the left sensor (d) neither sensor
30. 30.🔦 A light sensor reads 10 over black and 90 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 47. What is under the sensor? (a) the black line (b) the white floor
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 75. Which sensor is over the black line? (a) both sensors (b) neither sensor (c) the right sensor (d) the left sensor
33. 33.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 65 and the right sensor reads 40. Which sensor is over the black line? (a) the left sensor (b) the right sensor (c) neither sensor (d) both sensors
34. 34.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 15 and the right sensor reads 40. Which sensor is over the black line? (a) the left sensor (b) both sensors (c) the right sensor (d) neither sensor
35. 35.🔦 A light sensor reads 20 over black and 70 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 10 and the right sensor reads 60. Which sensor is over the black line? (a) the left sensor (b) the right sensor (c) neither sensor (d) both sensors
37. 37.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 30 and the right sensor reads 80. Which sensor is over the black line? (a) the left sensor (b) both sensors (c) the right sensor (d) neither sensor
38. 38.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 35. What is under the sensor? (a) the black line (b) the white floor
39. 39.🔦 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) the right sensor (b) both sensors (c) neither sensor (d) the left sensor
40. 40.🔦 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 black line (b) the white floor

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