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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 696 · 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.🔁 What must there be for a current to flow? (a) a broken path (b) one loose end (c) a plastic gap (d) a complete loop
  2. 2.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
  3. 3.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) both of them (b) it does not matter (c) only one (d) none
  4. 4.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
  5. 5.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
  6. 6.Which of these means the circuit is closed? (a) a wire has come loose (b) the bulb is unscrewed (c) the switch is OFF (d) the switch is ON
  7. 7.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the switch (b) the glass (c) the base (d) the filament
  8. 8.🔦 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 steel coin. Does the bulb glow? (a) No (b) Yes
  9. 9.🔦 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) Yes (b) No
  10. 10.🔦 A circuit has a used-up (dead) cell, a good bulb and a switch that is ON. All the wires are firmly joined. Does the bulb glow? (a) Yes (b) No
  11. 11.True or false: if a cell is taken out, the circuit is closed and current flows. (a) False (b) True
  12. 12.🔦 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 aluminium foil. Does the bulb glow? (a) Yes (b) No
  13. 13.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
  14. 14.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
  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 brass key. Does the bulb glow? (a) No (b) Yes
  16. 16.🔦 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 rubber band. 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. One wire has come loose from the cell. A gap in one wire is bridged by a plastic ruler. Does the bulb glow? (a) Yes (b) No
  18. 18.🔁 What do we call a circuit with a break in it? (a) an open circuit (b) a full circuit (c) a series circuit (d) a closed circuit
  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 steel coin. Does the bulb glow? (a) Yes (b) No
  20. 20.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. Does the bulb glow? (a) No (b) Yes
  21. 21.True or false: if the loop is complete, the circuit is open and no current flows. (a) True (b) False
  22. 22.🔦 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) Yes (b) No
  23. 23.Which of these means the circuit is open? (a) all wires are joined (b) the loop is complete (c) the switch is ON (d) a wire has come loose
  24. 24.🔦 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 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 an iron nail. Does the bulb glow? (a) Yes (b) No
  26. 26.Which of these means the circuit is closed? (a) a wire has come loose (b) the bulb is unscrewed (c) all wires are joined (d) the switch is OFF
  27. 27.🔦 A circuit has a new cell, a good bulb and a switch that is ON. One wire has come loose from the cell. Does the bulb glow? (a) No (b) Yes
  28. 28.🔦 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
  29. 29.True or false: if all wires are joined, the circuit is closed and current flows. (a) False (b) True
  30. 30.🔦 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) Yes (b) No
  31. 31.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
  32. 32.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
  33. 33.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
  34. 34.🔦 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 paper strip. Does the bulb glow? (a) Yes (b) No
  35. 35.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) the switch is ON (d) the bulb is unscrewed
  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 woollen thread. Does the bulb glow? (a) No (b) Yes
  37. 37.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
  38. 38.Which of these means the circuit is open? (a) a wire is cut (b) all wires are joined (c) the switch is ON (d) the loop is complete
  39. 39.True or false: if a wire has come loose, the circuit is closed and current flows. (a) True (b) False
  40. 40.Which of these means the circuit is closed? (a) the switch is OFF (b) the loop is complete (c) a wire has come loose (d) the bulb is unscrewed

Answer key

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

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