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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 325 · 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 complete loop (b) one loose end (c) a broken path (d) a plastic gap
  2. 2.🔦 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 plastic ruler. Does the bulb glow? (a) Yes (b) No
  3. 3.🔦 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 wooden stick. Does the bulb glow? (a) No (b) Yes
  4. 4.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
  5. 5.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
  6. 6.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
  7. 7.True or false: if all wires are joined, the circuit is closed and current flows. (a) False (b) True
  8. 8.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
  9. 9.🔦 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) Yes (b) No
  10. 10.True or false: if a wire has come loose, the circuit is closed and current flows. (a) False (b) True
  11. 11.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
  12. 12.🔦 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
  13. 13.Which of these means the circuit is closed? (a) a wire has come loose (b) a cell is taken out (c) the bulb is unscrewed (d) all wires are joined
  14. 14.True or false: if a wire is cut, the circuit is closed and current flows. (a) False (b) True
  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 graphite rod. Does the bulb glow? (a) Yes (b) No
  16. 16.True or false: if the switch is ON, the circuit is closed and current flows. (a) False (b) True
  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 cotton thread. Does the bulb glow? (a) No (b) Yes
  18. 18.🔦 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 wooden stick. Does the bulb glow? (a) Yes (b) No
  19. 19.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the glass (c) the filament (d) the switch
  20. 20.🔦 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) No (b) Yes
  21. 21.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
  22. 22.🔦 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) Yes (b) No
  23. 23.🔦 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
  24. 24.Which of these means the circuit is open? (a) a wire has come loose (b) the loop is complete (c) the switch is ON (d) all wires are joined
  25. 25.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) it does not matter (b) none (c) only one (d) both of them
  26. 26.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) the switch is ON (d) a wire is cut
  27. 27.🔦 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) No (b) Yes
  28. 28.Which of these means the circuit is closed? (a) the switch is OFF (b) the switch is ON (c) a wire has come loose (d) a cell is taken out
  29. 29.🔦 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
  30. 30.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
  31. 31.🔦 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
  32. 32.🔦 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 plastic straw. Does the bulb glow? (a) Yes (b) No
  33. 33.🔦 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
  34. 34.🔦 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 cotton thread. Does the bulb glow? (a) Yes (b) No
  35. 35.True or false: if a wire has come loose, the circuit is open and no current flows. (a) False (b) True
  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) Yes (b) No
  37. 37.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
  38. 38.🔦 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
  39. 39.True or false: if the loop is complete, the circuit is open and no current flows. (a) True (b) False
  40. 40.🔦 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 steel coin. Does the bulb glow? (a) No (b) Yes

Answer key

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

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