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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 721 · 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.🔦 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) Yes (b) No
  2. 2.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
  3. 3.🔦 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 safety pin. Does the bulb glow? (a) No (b) Yes
  4. 4.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
  5. 5.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the switch (b) the filament (c) the base (d) the glass
  6. 6.🔦 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
  7. 7.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
  8. 8.True or false: if a wire has come loose, the circuit is closed and current flows. (a) True (b) False
  9. 9.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
  10. 10.🔦 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
  11. 11.True or false: if the switch is OFF, the circuit is closed and current flows. (a) True (b) False
  12. 12.🔁 What do we call a circuit with a break in it? (a) a closed circuit (b) an open circuit (c) a series circuit (d) a full circuit
  13. 13.🔦 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 coin. Does the bulb glow? (a) No (b) Yes
  14. 14.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
  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 paper strip. Does the bulb glow? (a) No (b) Yes
  16. 16.🔦 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 plastic ruler. Does the bulb glow? (a) Yes (b) No
  17. 17.True or false: if the switch is ON, the circuit is closed and current flows. (a) False (b) True
  18. 18.🔦 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) Yes (b) No
  19. 19.Which of these means the circuit is open? (a) the switch is ON (b) all wires are joined (c) the loop is complete (d) the switch is OFF
  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) Yes (b) No
  21. 21.Which of these means the circuit is open? (a) the switch is ON (b) the loop is complete (c) a wire is cut (d) all wires are joined
  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 dry cork. Does the bulb glow? (a) Yes (b) No
  23. 23.Which of these means the circuit is open? (a) a cell is taken out (b) all wires are joined (c) the loop is complete (d) the switch is ON
  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 steel coin. Does the bulb glow? (a) Yes (b) No
  25. 25.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) none (b) it does not matter (c) only one (d) both of them
  26. 26.🔦 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
  27. 27.🔦 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 metal paper clip. Does the bulb glow? (a) No (b) Yes
  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 steel spoon. Does the bulb glow? (a) Yes (b) No
  29. 29.True or false: if a cell is taken out, the circuit is closed and current flows. (a) True (b) False
  30. 30.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
  31. 31.🔁 What must there be for a current to flow? (a) one loose end (b) a broken path (c) a complete loop (d) a plastic gap
  32. 32.True or false: if all wires are joined, the circuit is closed and current flows. (a) False (b) True
  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 aluminium foil. Does the bulb glow? (a) Yes (b) No
  34. 34.🔦 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) Yes (b) No
  35. 35.True or false: if a cell is taken out, the circuit is open and no current flows. (a) True (b) False
  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 rubber eraser. Does the bulb glow? (a) Yes (b) No
  37. 37.🔦 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 coin. Does the bulb glow? (a) No (b) Yes
  38. 38.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
  39. 39.Which of these means the circuit is closed? (a) a wire is cut (b) a cell is taken out (c) the loop is complete (d) a wire has come loose
  40. 40.🔦 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) Yes (b) No

Answer key

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

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