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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 159 · 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 plastic gap (d) a broken path
  2. 2.🔦 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
  3. 3.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) both of them (b) it does not matter (c) none (d) only one
  4. 4.Which of these means the circuit is closed? (a) a wire is cut (b) all wires are joined (c) the switch is OFF (d) a cell is taken out
  5. 5.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the switch (c) the glass (d) the filament
  6. 6.True or false: if the switch is ON, the circuit is closed and current flows. (a) False (b) True
  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 rubber eraser. 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. 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
  9. 9.🔦 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 rubber eraser. Does the bulb glow? (a) No (b) Yes
  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 a ceramic cup. Does the bulb glow? (a) No (b) Yes
  11. 11.True or false: if the switch is OFF, the circuit is open and no current flows. (a) False (b) True
  12. 12.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
  13. 13.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) False (b) True
  14. 14.🔦 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
  15. 15.🔦 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
  16. 16.🔦 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
  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 rubber eraser. Does the bulb glow? (a) No (b) Yes
  18. 18.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
  19. 19.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
  20. 20.🔦 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 rubber band. Does the bulb glow? (a) No (b) Yes
  21. 21.True or false: if a wire is cut, the circuit is closed and current flows. (a) False (b) True
  22. 22.Which of these means the circuit is open? (a) the loop is complete (b) a cell is taken out (c) the switch is ON (d) all wires are joined
  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 a steel spoon. Does the bulb glow? (a) Yes (b) No
  24. 24.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
  25. 25.🔦 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) No (b) Yes
  26. 26.True or false: if the loop is complete, the circuit is closed and current flows. (a) False (b) True
  27. 27.True or false: if a cell is taken out, 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 loop is complete (c) the switch is OFF (d) the switch is ON
  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 brass key. 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.Which of these means the circuit is open? (a) the switch is ON (b) a wire is cut (c) the loop is complete (d) all wires are joined
  32. 32.🔦 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) No (b) Yes
  33. 33.🔦 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 metal paper clip. 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 plastic straw. Does the bulb glow? (a) No (b) Yes
  35. 35.Which of these means the circuit is closed? (a) a wire is cut (b) the loop is complete (c) a wire has come loose (d) the switch is OFF
  36. 36.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
  37. 37.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
  38. 38.🔦 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
  39. 39.🔦 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
  40. 40.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

Answer key

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

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