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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 489 · 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) one loose end (b) a broken path (c) a plastic gap (d) a complete loop
  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. Does the bulb glow? (a) No (b) Yes
  3. 3.🔦 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
  4. 4.Which of these means the circuit is open? (a) all wires are joined (b) a cell is taken out (c) the loop is complete (d) the switch is ON
  5. 5.🔦 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
  6. 6.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
  7. 7.True or false: if a wire has come loose, the circuit is closed and current flows. (a) False (b) True
  8. 8.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
  9. 9.Which of these means the circuit is closed? (a) a wire has come loose (b) the switch is ON (c) a wire is cut (d) the bulb is unscrewed
  10. 10.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
  11. 11.🔦 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 an iron nail. Does the bulb glow? (a) Yes (b) No
  12. 12.Which of these means the circuit is closed? (a) a wire has come loose (b) the switch is OFF (c) a wire is cut (d) the loop is complete
  13. 13.True or false: if the switch is OFF, the circuit is closed and current flows. (a) False (b) True
  14. 14.🔦 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 plastic ruler. Does the bulb glow? (a) Yes (b) No
  15. 15.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
  16. 16.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
  17. 17.🔦 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
  18. 18.🔦 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 dry cork. Does the bulb glow? (a) Yes (b) No
  19. 19.True or false: if all wires are joined, the circuit is closed and current flows. (a) False (b) True
  20. 20.🔦 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
  21. 21.🔦 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) Yes (b) No
  22. 22.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
  23. 23.True or false: if a wire is cut, the circuit is closed and current flows. (a) True (b) False
  24. 24.🔁 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) both of them (d) only one
  25. 25.🔦 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
  26. 26.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the switch (c) the filament (d) the glass
  27. 27.True or false: if the switch is ON, the circuit is closed and current flows. (a) True (b) False
  28. 28.🔦 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 copper wire. Does the bulb glow? (a) No (b) Yes
  29. 29.🔦 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 brass key. Does the bulb glow? (a) No (b) Yes
  30. 30.Which of these means the circuit is closed? (a) the switch is OFF (b) a wire has come loose (c) a wire is cut (d) all wires are joined
  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 rubber band. Does the bulb glow? (a) No (b) Yes
  32. 32.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
  33. 33.True or false: if the switch is OFF, the circuit is open and no current flows. (a) False (b) True
  34. 34.True or false: if the switch is ON, the circuit is open and no current flows. (a) True (b) False
  35. 35.Which of these means the circuit is open? (a) a wire has come loose (b) all wires are joined (c) the switch is ON (d) the loop is complete
  36. 36.True or false: if all wires are joined, the circuit is open and no current flows. (a) False (b) True
  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 ceramic cup. 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 a steel coin. Does the bulb glow? (a) No (b) Yes
  39. 39.🔦 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 graphite rod. Does the bulb glow? (a) Yes (b) No
  40. 40.🔦 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) No (b) Yes

Answer key

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

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