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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 309 · 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 plastic gap (b) one loose end (c) a complete loop (d) a broken path
  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. A gap in one wire is bridged by an iron nail. Does the bulb glow? (a) Yes (b) No
  3. 3.True or false: if a wire has come loose, the circuit is open and no current flows. (a) True (b) False
  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.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the filament (c) the switch (d) the glass
  6. 6.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) none (b) only one (c) it does not matter (d) both of them
  7. 7.Which of these means the circuit is closed? (a) a wire has come loose (b) the bulb is unscrewed (c) the loop is complete (d) the switch is OFF
  8. 8.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) a wire is cut (d) the switch is ON
  9. 9.🔦 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
  10. 10.🔁 What do we call a circuit with a break in it? (a) a closed circuit (b) a series circuit (c) an open circuit (d) a full circuit
  11. 11.Which of these means the circuit is closed? (a) a wire has come loose (b) a wire is cut (c) all wires are joined (d) the bulb is unscrewed
  12. 12.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
  13. 13.Which of these means the circuit is open? (a) all wires are joined (b) the switch is ON (c) the switch is OFF (d) the loop is complete
  14. 14.Which of these means the circuit is closed? (a) a wire has come loose (b) the switch is OFF (c) the switch is ON (d) the bulb is unscrewed
  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 copper wire. Does the bulb glow? (a) Yes (b) No
  16. 16.True or false: if all wires are joined, the circuit is closed and current flows. (a) False (b) True
  17. 17.True or false: if the switch is OFF, the circuit is closed and current flows. (a) True (b) False
  18. 18.🔦 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) Yes (b) No
  19. 19.True or false: if a wire has come loose, the circuit is closed and current flows. (a) True (b) False
  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 rubber band. Does the bulb glow? (a) Yes (b) No
  21. 21.🔦 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 aluminium foil. Does the bulb glow? (a) No (b) Yes
  22. 22.🔦 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
  23. 23.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
  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 paper strip. Does the bulb glow? (a) Yes (b) No
  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 dry cork. Does the bulb glow? (a) No (b) Yes
  26. 26.🔦 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 graphite rod. Does the bulb glow? (a) No (b) Yes
  27. 27.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
  28. 28.Which of these means the circuit is open? (a) all wires are joined (b) the switch is ON (c) a wire has come loose (d) the loop is complete
  29. 29.🔦 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) No (b) Yes
  30. 30.🔦 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) No (b) Yes
  31. 31.True or false: if a wire is cut, the circuit is closed and current flows. (a) False (b) True
  32. 32.🔦 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
  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 safety pin. Does the bulb glow? (a) Yes (b) No
  34. 34.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
  35. 35.Which of these means the circuit is open? (a) the loop is complete (b) the bulb is unscrewed (c) the switch is ON (d) all wires are joined
  36. 36.Which of these means the circuit is open? (a) the switch is ON (b) the loop is complete (c) a cell is taken out (d) all wires are joined
  37. 37.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
  38. 38.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
  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 steel coin. Does the bulb glow? (a) No (b) Yes
  40. 40.True or false: if the switch is ON, the circuit is closed and current flows. (a) False (b) True

Answer key

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

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