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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 411 · 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.True or false: if the loop is complete, the circuit is open and no current flows. (a) False (b) True
  2. 2.🔁 What do we call a circuit with a break in it? (a) a full circuit (b) an open circuit (c) a series circuit (d) a closed circuit
  3. 3.True or false: if a wire is cut, the circuit is closed and current flows. (a) False (b) True
  4. 4.🔦 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
  5. 5.Which of these means the circuit is closed? (a) a wire has come loose (b) a cell is taken out (c) the loop is complete (d) a wire is cut
  6. 6.🔦 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) Yes (b) No
  7. 7.🔦 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 steel spoon. Does the bulb glow? (a) Yes (b) No
  8. 8.🔁 What must there be for a current to flow? (a) a plastic gap (b) a broken path (c) a complete loop (d) one loose end
  9. 9.True or false: if all wires are joined, the circuit is closed and current flows. (a) True (b) False
  10. 10.Which of these means the circuit is open? (a) the switch is OFF (b) all wires are joined (c) the loop is complete (d) the switch is ON
  11. 11.🔦 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 copper wire. Does the bulb glow? (a) No (b) Yes
  12. 12.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
  13. 13.🔦 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) Yes (b) No
  14. 14.🔁 Is the circuit closed or open if a cell is taken out? (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 metal paper clip. 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 band. Does the bulb glow? (a) Yes (b) No
  17. 17.🔦 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
  18. 18.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) all wires are joined
  19. 19.Which of these means the circuit is open? (a) a wire has come loose (b) the loop is complete (c) all wires are joined (d) the switch is ON
  20. 20.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) it does not matter (b) only one (c) none (d) both of them
  21. 21.🔦 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
  22. 22.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) a wire is cut (c) the switch is ON (d) a cell is taken out
  23. 23.🔦 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 aluminium foil. Does the bulb glow? (a) Yes (b) No
  24. 24.🔦 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 graphite rod. Does the bulb glow? (a) No (b) Yes
  25. 25.🔦 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 ceramic cup. Does the bulb glow? (a) No (b) Yes
  26. 26.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
  27. 27.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
  28. 28.🔦 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) Yes (b) No
  29. 29.True or false: if the switch is ON, the circuit is closed and current flows. (a) False (b) True
  30. 30.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
  31. 31.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) True (b) False
  32. 32.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
  33. 33.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
  34. 34.True or false: if the switch is OFF, the circuit is open and no current flows. (a) True (b) False
  35. 35.🔦 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 dry cork. Does the bulb glow? (a) Yes (b) No
  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 glass marble. Does the bulb glow? (a) No (b) Yes
  37. 37.🔦 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 safety pin. Does the bulb glow? (a) Yes (b) No
  38. 38.🔦 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) No (b) Yes
  39. 39.🔦 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
  40. 40.Which of these means the circuit is open? (a) the bulb is unscrewed (b) the switch is ON (c) the loop is complete (d) all wires are joined

Answer key

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

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