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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 291 · 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.Which of these means the circuit is open? (a) a cell is taken out (b) the switch is ON (c) the loop is complete (d) all wires are joined
  2. 2.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
  3. 3.🔦 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
  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 dry cork. Does the bulb glow? (a) Yes (b) No
  5. 5.🔦 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
  6. 6.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the filament (c) the switch (d) the glass
  7. 7.🔦 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
  8. 8.🔦 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
  9. 9.🔁 What must there be for a current to flow? (a) a broken path (b) a plastic gap (c) a complete loop (d) one loose end
  10. 10.🔦 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
  11. 11.🔁 What do we call a circuit with a break in it? (a) a closed circuit (b) a series circuit (c) a full circuit (d) an open circuit
  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 paper strip. Does the bulb glow? (a) Yes (b) No
  13. 13.Which of these means the circuit is open? (a) all wires are joined (b) the bulb is unscrewed (c) the switch is ON (d) the loop is complete
  14. 14.True or false: if a wire has come loose, the circuit is open and no current flows. (a) True (b) False
  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 woollen thread. Does the bulb glow? (a) Yes (b) No
  16. 16.Which of these means the circuit is open? (a) the switch is OFF (b) the loop is complete (c) the switch is ON (d) all wires are joined
  17. 17.🔦 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) Yes (b) No
  18. 18.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
  19. 19.🔦 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
  20. 20.True or false: if a wire is cut, the circuit is closed and current flows. (a) False (b) True
  21. 21.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
  22. 22.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 wire has come loose
  23. 23.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
  24. 24.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
  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 rubber eraser. Does the bulb glow? (a) Yes (b) No
  26. 26.🔦 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 brass key. Does the bulb glow? (a) Yes (b) No
  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 spoon. Does the bulb glow? (a) Yes (b) No
  28. 28.Which of these means the circuit is closed? (a) the switch is OFF (b) a wire has come loose (c) the switch is ON (d) a wire is cut
  29. 29.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) True (b) False
  30. 30.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
  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 a plastic ruler. Does the bulb glow? (a) No (b) Yes
  32. 32.Which of these means the circuit is closed? (a) the switch is OFF (b) the loop is complete (c) a cell is taken out (d) a wire is cut
  33. 33.🔦 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 woollen thread. Does the bulb glow? (a) No (b) Yes
  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 copper wire. Does the bulb glow? (a) No (b) Yes
  35. 35.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) only one (b) none (c) it does not matter (d) both of them
  36. 36.🔦 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 graphite rod. Does the bulb glow? (a) Yes (b) No
  37. 37.🔦 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 glass marble. Does the bulb glow? (a) No (b) Yes
  38. 38.🔦 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) No (b) Yes
  39. 39.True or false: if the loop is complete, the circuit is closed and current flows. (a) True (b) False
  40. 40.True or false: if all wires are joined, the circuit is closed and current flows. (a) True (b) False

Answer key

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

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