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Electronics Worksheet: Loops and Variables

Electronics lesson 25: Loops and variables · Set 254 · 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) stores a value (b) joins two wires (c) measures light (d) blinks an LED
  2. 2.🔁 count = 0
    while (count < 9) { count = count + 3 }
    How many times does the loop run?
  3. 3.🔁 total = 0
    for i = 1 to 8 { total = total + i }
    What is total at the end?
  4. 4.🔁 count = 0
    repeat 9 times { count = count + 4 }
    What is count at the end?
  5. 5.🔁 x = 3
    repeat 4 times { x = x × 2 }
    What is x at the end?
  6. 6.🔁 count = 5
    repeat 4 times { count = count + 7 }
    What is count at the end?
  7. 7.🔁 What does “count = count + 1” do? (a) sets count to 1 (b) takes 1 away (c) adds 1 to count (d) prints 1
  8. 8.🔁 count = 0
    repeat 2 times { count = count + 2 }
    What is count at the end?
  9. 9.🔁 total = 0
    for i = 1 to 12 { total = total + i }
    What is total at the end?
  10. 10.🔁 count = 6
    repeat 10 times { count = count + 3 }
    What is count at the end?
  11. 11.🔁 repeat 5 times { repeat 6 times { beep } }
    How many beeps are there?
  12. 12.🔁 count = 10
    repeat 5 times { count = count + 9 }
    What is count at the end?
  13. 13.🔁 count = 5
    while (count < 25) { count = count + 5 }
    How many times does the loop run?
  14. 14.🔁 x = 5
    repeat 4 times { x = x × 2 }
    What is x at the end?
  15. 15.🔁 count = 3
    repeat 8 times { count = count + 5 }
    What is count at the end?
  16. 16.🔁 repeat 4 times { repeat 3 times { beep } }
    How many beeps are there?
  17. 17.🔁 repeat 2 times { repeat 5 times { beep } }
    How many beeps are there?
  18. 18.🔁 repeat 2 times { repeat 2 times { beep } }
    How many beeps are there?
  19. 19.🔁 total = 0
    for i = 1 to 5 { total = total + i }
    What is total at the end?
  20. 20.🔁 x = 4
    repeat 3 times { x = x × 2 }
    What is x at the end?
  21. 21.🔁 x = 2
    repeat 4 times { x = x × 2 }
    What is x at the end?
  22. 22.🔁 count = 4
    while (count < 16) { count = count + 3 }
    How many times does the loop run?
  23. 23.🔁 repeat 6 times { repeat 4 times { beep } }
    How many beeps are there?
  24. 24.🔁 x = 1
    repeat 1 time { x = x × 2 }
    What is x at the end?
  25. 25.🔁 x = 5
    repeat 1 time { x = x × 2 }
    What is x at the end?
  26. 26.🔁 count = 10
    repeat 5 times { count = count + 5 }
    What is count at the end?
  27. 27.🔁 count = 4
    while (count < 8) { count = count + 2 }
    How many times does the loop run?
  28. 28.🔁 total = 0
    for i = 1 to 6 { total = total + i }
    What is total at the end?
  29. 29.🔁 count = 1
    while (count < 31) { count = count + 5 }
    How many times does the loop run?
  30. 30.🔁 count = 10
    repeat 3 times { count = count + 6 }
    What is count at the end?
  31. 31.🔁 count = 1
    while (count < 17) { count = count + 2 }
    How many times does the loop run?
  32. 32.🔁 total = 0
    for i = 1 to 7 { total = total + i }
    What is total at the end?
  33. 33.🔁 count = 8
    repeat 2 times { count = count + 5 }
    What is count at the end?
  34. 34.🔁 x = 4
    repeat 4 times { x = x × 2 }
    What is x at the end?
  35. 35.🔁 total = 0
    for i = 1 to 3 { total = total + i }
    What is total at the end?
  36. 36.🔁 x = 3
    repeat 1 time { x = x × 2 }
    What is x at the end?
  37. 37.🔁 repeat 4 times { repeat 4 times { beep } }
    How many beeps are there?
  38. 38.🔁 count = 7
    repeat 3 times { count = count + 3 }
    What is count at the end?
  39. 39.🔁 total = 0
    for i = 1 to 10 { total = total + i }
    What is total at the end?
  40. 40.🔁 x = 4
    repeat 2 times { x = x × 2 }
    What is x at the end?

Answer key

  1. stores a value
  2. 3
  3. 36
  4. 36
  5. 48
  6. 33
  7. adds 1 to count
  8. 4
  9. 78
  10. 36
  11. 30
  12. 55
  13. 4
  14. 80
  15. 43
  16. 12
  17. 10
  18. 4
  19. 15
  20. 32
  21. 32
  22. 4
  23. 24
  24. 2
  25. 10
  26. 35
  27. 2
  28. 21
  29. 6
  30. 28
  31. 8
  32. 28
  33. 18
  34. 64
  35. 6
  36. 6
  37. 16
  38. 16
  39. 55
  40. 16

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