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Electronics Worksheet: Loops and Variables

Electronics lesson 25: Loops and variables · Set 12 · 40 questions
TalentJR

Remember (Trace every pass): count = count + k adds k each time round; after n rounds: start + n × k. A loop inside a loop runs outer × inner times. while (condition) repeats until the condition is false — count the rounds as you trace.

NameDateTime takenScore ___ / 40
  1. 1.🔁 What does a variable do in a program? (a) joins two wires (b) stores a value (c) blinks an LED (d) measures light
  2. 2.🔁 count = 6
    repeat 3 times { count = count + 9 }
    What is count at the end?
  3. 3.🔁 count = 8
    repeat 8 times { count = count + 2 }
    What is count at the end?
  4. 4.🔁 repeat 6 times { repeat 4 times { beep } }
    How many beeps are there?
  5. 5.🔁 repeat 5 times { repeat 5 times { beep } }
    How many beeps are there?
  6. 6.🔁 count = 0
    repeat 5 times { count = count + 3 }
    What is count at the end?
  7. 7.🔁 x = 2
    repeat 2 times { x = x × 2 }
    What is x at the end?
  8. 8.🔁 x = 4
    repeat 1 time { x = x × 2 }
    What is x at the end?
  9. 9.🔁 count = 1
    while (count < 13) { count = count + 2 }
    How many times does the loop run?
  10. 10.🔁 count = 1
    while (count < 41) { count = count + 5 }
    How many times does the loop run?
  11. 11.🔁 x = 5
    repeat 1 time { x = x × 2 }
    What is x at the end?
  12. 12.🔁 x = 2
    repeat 1 time { x = x × 2 }
    What is x at the end?
  13. 13.🔁 What does “count = count + 1” do? (a) prints 1 (b) adds 1 to count (c) takes 1 away (d) sets count to 1
  14. 14.🔁 x = 1
    repeat 1 time { x = x × 2 }
    What is x at the end?
  15. 15.🔁 count = 8
    repeat 10 times { count = count + 5 }
    What is count at the end?
  16. 16.🔁 x = 3
    repeat 3 times { x = x × 2 }
    What is x at the end?
  17. 17.🔁 count = 3
    repeat 7 times { count = count + 2 }
    What is count at the end?
  18. 18.🔁 count = 3
    repeat 2 times { count = count + 2 }
    What is count at the end?
  19. 19.🔁 repeat 3 times { repeat 5 times { beep } }
    How many beeps are there?
  20. 20.🔁 count = 8
    repeat 6 times { count = count + 6 }
    What is count at the end?
  21. 21.🔁 count = 6
    repeat 10 times { count = count + 9 }
    What is count at the end?
  22. 22.🔁 total = 0
    for i = 1 to 11 { total = total + i }
    What is total at the end?
  23. 23.🔁 x = 4
    repeat 3 times { x = x × 2 }
    What is x at the end?
  24. 24.🔁 count = 0
    while (count < 24) { count = count + 3 }
    How many times does the loop run?
  25. 25.🔁 repeat 2 times { repeat 6 times { beep } }
    How many beeps are there?
  26. 26.🔁 total = 0
    for i = 1 to 3 { total = total + i }
    What is total at the end?
  27. 27.🔁 repeat 5 times { repeat 3 times { beep } }
    How many beeps are there?
  28. 28.🔁 total = 0
    for i = 1 to 10 { total = total + i }
    What is total at the end?
  29. 29.🔁 repeat 6 times { repeat 2 times { beep } }
    How many beeps are there?
  30. 30.🔁 total = 0
    for i = 1 to 12 { total = total + i }
    What is total at the end?
  31. 31.🔁 count = 9
    repeat 3 times { count = count + 2 }
    What is count at the end?
  32. 32.🔁 count = 0
    repeat 6 times { count = count + 8 }
    What is count at the end?
  33. 33.🔁 count = 2
    repeat 8 times { count = count + 8 }
    What is count at the end?
  34. 34.🔁 total = 0
    for i = 1 to 4 { total = total + i }
    What is total at the end?
  35. 35.🔁 count = 1
    repeat 5 times { count = count + 8 }
    What is count at the end?
  36. 36.🔁 count = 5
    while (count < 20) { count = count + 3 }
    How many times does the loop run?
  37. 37.🔁 count = 5
    repeat 4 times { count = count + 7 }
    What is count at the end?
  38. 38.🔁 count = 4
    while (count < 16) { count = count + 2 }
    How many times does the loop run?
  39. 39.🔁 repeat 3 times { repeat 3 times { beep } }
    How many beeps are there?
  40. 40.🔁 repeat 3 times { repeat 2 times { beep } }
    How many beeps are there?

Answer key

  1. stores a value
  2. 33
  3. 24
  4. 24
  5. 25
  6. 15
  7. 8
  8. 8
  9. 6
  10. 8
  11. 10
  12. 4
  13. adds 1 to count
  14. 2
  15. 58
  16. 24
  17. 17
  18. 7
  19. 15
  20. 44
  21. 96
  22. 66
  23. 32
  24. 8
  25. 12
  26. 6
  27. 15
  28. 55
  29. 12
  30. 78
  31. 15
  32. 48
  33. 66
  34. 10
  35. 41
  36. 5
  37. 33
  38. 6
  39. 9
  40. 6

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