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Electronics Worksheet: Loops and Variables

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

Answer key

  1. adds 1 to count
  2. 2
  3. 28
  4. 4
  5. 18
  6. 12
  7. 44
  8. 10
  9. 4
  10. 4
  11. stores a value
  12. 65
  13. 38
  14. 7
  15. 6
  16. 41
  17. 21
  18. 16
  19. 12
  20. 4
  21. 20
  22. 36
  23. 3
  24. 32
  25. 12
  26. 32
  27. 3
  28. 24
  29. 6
  30. 2
  31. 6
  32. 80
  33. 6
  34. 21
  35. 2
  36. 10
  37. 12
  38. 47
  39. 10
  40. 7

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