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Electronics Worksheet: Loops and Variables

Electronics lesson 25: Loops and variables · Set 17 · 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) blinks an LED (c) stores a value (d) measures light
  2. 2.🔁 count = 7
    repeat 5 times { count = count + 4 }
    What is count at the end?
  3. 3.🔁 count = 2
    repeat 10 times { count = count + 10 }
    What is count at the end?
  4. 4.🔁 total = 0
    for i = 1 to 10 { total = total + i }
    What is total at the end?
  5. 5.🔁 x = 5
    repeat 5 times { x = x × 2 }
    What is x at the end?
  6. 6.🔁 count = 9
    repeat 9 times { count = count + 9 }
    What is count at the end?
  7. 7.🔁 total = 0
    for i = 1 to 11 { total = total + i }
    What is total at the end?
  8. 8.🔁 What does “count = count + 1” do? (a) adds 1 to count (b) sets count to 1 (c) takes 1 away (d) prints 1
  9. 9.🔁 count = 4
    while (count < 16) { count = count + 2 }
    How many times does the loop run?
  10. 10.🔁 x = 2
    repeat 5 times { x = x × 2 }
    What is x at the end?
  11. 11.🔁 count = 5
    while (count < 19) { count = count + 2 }
    How many times does the loop run?
  12. 12.🔁 count = 5
    repeat 7 times { count = count + 4 }
    What is count at the end?
  13. 13.🔁 count = 3
    while (count < 15) { count = count + 3 }
    How many times does the loop run?
  14. 14.🔁 count = 2
    repeat 2 times { count = count + 9 }
    What is count at the end?
  15. 15.🔁 x = 3
    repeat 2 times { x = x × 2 }
    What is x at the end?
  16. 16.🔁 total = 0
    for i = 1 to 7 { total = total + i }
    What is total at the end?
  17. 17.🔁 count = 5
    repeat 6 times { count = count + 10 }
    What is count at the end?
  18. 18.🔁 count = 2
    repeat 8 times { count = count + 3 }
    What is count at the end?
  19. 19.🔁 count = 1
    while (count < 19) { count = count + 3 }
    How many times does the loop run?
  20. 20.🔁 count = 3
    repeat 8 times { count = count + 3 }
    What is count at the end?
  21. 21.🔁 count = 3
    while (count < 18) { count = count + 3 }
    How many times does the loop run?
  22. 22.🔁 count = 9
    repeat 5 times { count = count + 3 }
    What is count at the end?
  23. 23.🔁 count = 9
    repeat 6 times { count = count + 2 }
    What is count at the end?
  24. 24.🔁 count = 10
    repeat 9 times { count = count + 5 }
    What is count at the end?
  25. 25.🔁 count = 10
    repeat 3 times { count = count + 9 }
    What is count at the end?
  26. 26.🔁 count = 2
    while (count < 27) { count = count + 5 }
    How many times does the loop run?
  27. 27.🔁 count = 0
    while (count < 9) { count = count + 3 }
    How many times does the loop run?
  28. 28.🔁 total = 0
    for i = 1 to 4 { total = total + i }
    What is total at the end?
  29. 29.🔁 x = 5
    repeat 1 time { x = x × 2 }
    What is x at the end?
  30. 30.🔁 count = 2
    repeat 8 times { count = count + 8 }
    What is count at the end?
  31. 31.🔁 count = 9
    repeat 7 times { count = count + 2 }
    What is count at the end?
  32. 32.🔁 total = 0
    for i = 1 to 12 { total = total + i }
    What is total at the end?
  33. 33.🔁 count = 0
    while (count < 12) { count = count + 2 }
    How many times does the loop run?
  34. 34.🔁 x = 1
    repeat 2 times { x = x × 2 }
    What is x at the end?
  35. 35.🔁 count = 5
    while (count < 25) { count = count + 4 }
    How many times does the loop run?
  36. 36.🔁 total = 0
    for i = 1 to 3 { total = total + i }
    What is total at the end?
  37. 37.🔁 count = 1
    repeat 4 times { count = count + 2 }
    What is count at the end?
  38. 38.🔁 count = 0
    repeat 5 times { count = count + 2 }
    What is count at the end?
  39. 39.🔁 total = 0
    for i = 1 to 5 { total = total + i }
    What is total at the end?
  40. 40.🔁 count = 0
    repeat 5 times { count = count + 4 }
    What is count at the end?

Answer key

  1. stores a value
  2. 27
  3. 102
  4. 55
  5. 160
  6. 90
  7. 66
  8. adds 1 to count
  9. 6
  10. 64
  11. 7
  12. 33
  13. 4
  14. 20
  15. 12
  16. 28
  17. 65
  18. 26
  19. 6
  20. 27
  21. 5
  22. 24
  23. 21
  24. 55
  25. 37
  26. 5
  27. 3
  28. 10
  29. 10
  30. 66
  31. 23
  32. 78
  33. 6
  34. 4
  35. 5
  36. 6
  37. 9
  38. 10
  39. 15
  40. 20

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