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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 824 · 40 questions
TalentJR

Remember (Follow the loop): Closed circuit = complete loop = current flows; open circuit = a break = no current. Check every part: live cell, good bulb, switch ON, all wires joined, any gap bridged by a conductor. If even one check fails, the bulb does not glow.

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  1. 1.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
  2. 2.🔦 A circuit has a new cell, a bulb with a broken filament and a switch that is ON. All the wires are firmly joined. Does the bulb glow? (a) Yes (b) No
  3. 3.🔁 What must there be for a current to flow? (a) a plastic gap (b) a broken path (c) one loose end (d) a complete loop
  4. 4.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a steel spoon. Does the bulb glow? (a) No (b) Yes
  5. 5.True or false: if a cell is taken out, the circuit is closed and current flows. (a) False (b) True
  6. 6.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
  7. 7.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
  8. 8.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) a wire has come loose (d) the switch is ON
  9. 9.True or false: if the loop is complete, the circuit is closed and current flows. (a) True (b) False
  10. 10.True or false: if the switch is ON, the circuit is closed and current flows. (a) False (b) True
  11. 11.🔦 A circuit has a new cell, a bulb with a broken filament and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a plastic straw. Does the bulb glow? (a) No (b) Yes
  12. 12.Which of these means the circuit is closed? (a) a wire has come loose (b) the switch is OFF (c) the loop is complete (d) the bulb is unscrewed
  13. 13.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
  14. 14.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by an iron nail. Does the bulb glow? (a) No (b) Yes
  15. 15.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a rubber band. Does the bulb glow? (a) No (b) Yes
  16. 16.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a rubber eraser. Does the bulb glow? (a) No (b) Yes
  17. 17.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a glass marble. Does the bulb glow? (a) Yes (b) No
  18. 18.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a metal paper clip. Does the bulb glow? (a) No (b) Yes
  19. 19.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a ceramic cup. Does the bulb glow? (a) Yes (b) No
  20. 20.Which of these means the circuit is open? (a) all wires are joined (b) the switch is ON (c) the loop is complete (d) a cell is taken out
  21. 21.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) none (b) both of them (c) only one (d) it does not matter
  22. 22.True or false: if a wire has come loose, the circuit is closed and current flows. (a) True (b) False
  23. 23.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
  24. 24.🔦 A circuit has a used-up (dead) cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a ceramic cup. Does the bulb glow? (a) No (b) Yes
  25. 25.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a wooden stick. Does the bulb glow? (a) No (b) Yes
  26. 26.🔦 A circuit has a new cell, a bulb with a broken filament and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a safety pin. Does the bulb glow? (a) No (b) Yes
  27. 27.🔦 A circuit has a new cell, a good bulb and a switch that is OFF. All the wires are firmly joined. A gap in one wire is bridged by a steel coin. Does the bulb glow? (a) Yes (b) No
  28. 28.True or false: if the switch is ON, the circuit is open and no current flows. (a) True (b) False
  29. 29.🔦 A circuit has a new cell, a good bulb and a switch that is ON. One wire has come loose from the cell. A gap in one wire is bridged by a dry cork. Does the bulb glow? (a) No (b) Yes
  30. 30.🔦 A circuit has a new cell, a bulb with a broken filament and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by an iron nail. Does the bulb glow? (a) Yes (b) No
  31. 31.Which of these means the circuit is closed? (a) the switch is ON (b) the switch is OFF (c) a wire has come loose (d) a cell is taken out
  32. 32.Which of these means the circuit is closed? (a) a wire is cut (b) all wires are joined (c) a wire has come loose (d) the bulb is unscrewed
  33. 33.🔦 A circuit has a new cell, a good bulb and a switch that is OFF. All the wires are firmly joined. Does the bulb glow? (a) No (b) Yes
  34. 34.🔦 A circuit has a new cell, a good bulb and a switch that is OFF. All the wires are firmly joined. A gap in one wire is bridged by a glass marble. Does the bulb glow? (a) No (b) Yes
  35. 35.🔦 A circuit has a new cell, a bulb with a broken filament and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a woollen thread. Does the bulb glow? (a) No (b) Yes
  36. 36.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a steel coin. Does the bulb glow? (a) No (b) Yes
  37. 37.True or false: if a cell is taken out, the circuit is open and no current flows. (a) True (b) False
  38. 38.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
  39. 39.True or false: if all wires are joined, the circuit is open and no current flows. (a) False (b) True
  40. 40.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the base (c) the filament (d) the switch

Answer key

  1. open
  2. No
  3. a complete loop
  4. Yes
  5. False
  6. open
  7. closed
  8. a wire has come loose
  9. True
  10. True
  11. No
  12. the loop is complete
  13. closed
  14. Yes
  15. No
  16. No
  17. No
  18. Yes
  19. No
  20. a cell is taken out
  21. both of them
  22. False
  23. open
  24. No
  25. No
  26. No
  27. No
  28. False
  29. No
  30. No
  31. the switch is ON
  32. all wires are joined
  33. No
  34. No
  35. No
  36. Yes
  37. True
  38. False
  39. False
  40. the filament

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