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Electronics Worksheet: Loops and Variables

Electronics lesson 25: Loops and variables · Set 507 · 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) measures light (b) joins two wires (c) stores a value (d) blinks an LED
  2. 2.🔁 count = 1
    while (count < 5) { count = count + 2 }
    How many times does the loop run?
  3. 3.🔁 repeat 3 times { repeat 6 times { beep } }
    How many beeps are there?
  4. 4.🔁 x = 4
    repeat 2 times { x = x × 2 }
    What is x at the end?
  5. 5.🔁 total = 0
    for i = 1 to 6 { total = total + i }
    What is total at the end?
  6. 6.🔁 x = 3
    repeat 4 times { x = x × 2 }
    What is x at the end?
  7. 7.🔁 total = 0
    for i = 1 to 8 { total = total + i }
    What is total at the end?
  8. 8.🔁 count = 6
    repeat 3 times { count = count + 6 }
    What is count at the end?
  9. 9.🔁 count = 1
    while (count < 29) { count = count + 4 }
    How many times does the loop run?
  10. 10.🔁 repeat 5 times { repeat 6 times { beep } }
    How many beeps are there?
  11. 11.🔁 repeat 2 times { repeat 5 times { beep } }
    How many beeps are there?
  12. 12.🔁 x = 5
    repeat 5 times { x = x × 2 }
    What is x at the end?
  13. 13.🔁 count = 6
    repeat 4 times { count = count + 4 }
    What is count at the end?
  14. 14.🔁 count = 3
    while (count < 21) { count = count + 3 }
    How many times does the loop run?
  15. 15.🔁 What does “count = count + 1” do? (a) takes 1 away (b) prints 1 (c) adds 1 to count (d) sets count to 1
  16. 16.🔁 repeat 6 times { repeat 4 times { beep } }
    How many beeps are there?
  17. 17.🔁 repeat 4 times { repeat 2 times { beep } }
    How many beeps are there?
  18. 18.🔁 repeat 2 times { repeat 4 times { beep } }
    How many beeps are there?
  19. 19.🔁 x = 4
    repeat 5 times { x = x × 2 }
    What is x at the end?
  20. 20.🔁 repeat 6 times { repeat 5 times { beep } }
    How many beeps are there?
  21. 21.🔁 count = 9
    repeat 10 times { count = count + 3 }
    What is count at the end?
  22. 22.🔁 repeat 4 times { repeat 3 times { beep } }
    How many beeps are there?
  23. 23.🔁 count = 2
    repeat 5 times { count = count + 5 }
    What is count at the end?
  24. 24.🔁 count = 3
    while (count < 15) { count = count + 3 }
    How many times does the loop run?
  25. 25.🔁 x = 3
    repeat 5 times { x = x × 2 }
    What is x at the end?
  26. 26.🔁 count = 3
    repeat 4 times { count = count + 8 }
    What is count at the end?
  27. 27.🔁 count = 4
    while (count < 32) { count = count + 4 }
    How many times does the loop run?
  28. 28.🔁 count = 5
    repeat 8 times { count = count + 4 }
    What is count at the end?
  29. 29.🔁 count = 6
    repeat 6 times { count = count + 6 }
    What is count at the end?
  30. 30.🔁 total = 0
    for i = 1 to 4 { total = total + i }
    What is total at the end?
  31. 31.🔁 repeat 6 times { repeat 2 times { beep } }
    How many beeps are there?
  32. 32.🔁 count = 4
    repeat 10 times { count = count + 3 }
    What is count at the end?
  33. 33.🔁 x = 5
    repeat 2 times { x = x × 2 }
    What is x at the end?
  34. 34.🔁 repeat 3 times { repeat 2 times { beep } }
    How many beeps are there?
  35. 35.🔁 repeat 6 times { repeat 3 times { beep } }
    How many beeps are there?
  36. 36.🔁 count = 2
    repeat 3 times { count = count + 5 }
    What is count at the end?
  37. 37.🔁 repeat 2 times { repeat 6 times { beep } }
    How many beeps are there?
  38. 38.🔁 count = 7
    repeat 4 times { count = count + 2 }
    What is count at the end?
  39. 39.🔁 repeat 5 times { repeat 4 times { beep } }
    How many beeps are there?
  40. 40.🔁 total = 0
    for i = 1 to 7 { total = total + i }
    What is total at the end?

Answer key

  1. stores a value
  2. 2
  3. 18
  4. 16
  5. 21
  6. 48
  7. 36
  8. 24
  9. 7
  10. 30
  11. 10
  12. 160
  13. 22
  14. 6
  15. adds 1 to count
  16. 24
  17. 8
  18. 8
  19. 128
  20. 30
  21. 39
  22. 12
  23. 27
  24. 4
  25. 96
  26. 35
  27. 7
  28. 37
  29. 42
  30. 10
  31. 12
  32. 34
  33. 20
  34. 6
  35. 18
  36. 17
  37. 12
  38. 15
  39. 20
  40. 28

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