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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 235 · 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) all wires are joined (b) the switch is ON (c) the bulb is unscrewed (d) the loop is complete
  2. 2.Which of these means the circuit is closed? (a) the switch is ON (b) the switch is OFF (c) a wire is cut (d) a wire has come loose
  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 a graphite rod. 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 paper strip. Does the bulb glow? (a) No (b) Yes
  5. 5.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
  6. 6.🔦 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
  7. 7.🔁 What do we call a circuit with a break in it? (a) an open circuit (b) a full circuit (c) a series circuit (d) a closed circuit
  8. 8.Which of these means the circuit is open? (a) a wire is cut (b) all wires are joined (c) the loop is complete (d) the switch is ON
  9. 9.🔦 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
  10. 10.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
  11. 11.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
  12. 12.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) False (b) True
  13. 13.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) a wire has come loose (c) the switch is OFF (d) all wires are joined
  14. 14.🔦 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
  15. 15.True or false: if the loop is complete, the circuit is open and no current flows. (a) True (b) False
  16. 16.Which of these means the circuit is open? (a) the loop is complete (b) a cell is taken out (c) all wires are joined (d) the switch is ON
  17. 17.🔦 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) Yes (b) No
  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 rubber band. Does the bulb glow? (a) Yes (b) No
  19. 19.🔦 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
  20. 20.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
  21. 21.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) both of them (b) none (c) it does not matter (d) only one
  22. 22.True or false: if a wire is cut, the circuit is open and no current flows. (a) False (b) True
  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 metal paper clip. Does the bulb glow? (a) Yes (b) No
  24. 24.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the switch (c) the base (d) the filament
  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 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 ceramic cup. Does the bulb glow? (a) Yes (b) No
  27. 27.🔦 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) Yes (b) No
  28. 28.🔁 What must there be for a current to flow? (a) a complete loop (b) a broken path (c) one loose end (d) a plastic gap
  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 steel coin. Does the bulb glow? (a) Yes (b) No
  30. 30.🔦 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
  31. 31.True or false: if a wire is cut, the circuit is closed and current flows. (a) True (b) False
  32. 32.🔦 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
  33. 33.Which of these means the circuit is open? (a) the loop is complete (b) the switch is ON (c) a wire has come loose (d) all wires are joined
  34. 34.🔦 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
  35. 35.🔦 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 straw. Does the bulb glow? (a) Yes (b) No
  36. 36.True or false: if the switch is OFF, the circuit is closed and current flows. (a) True (b) False
  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 copper wire. Does the bulb glow? (a) No (b) Yes
  38. 38.True or false: if the switch is OFF, the circuit is open and no current flows. (a) True (b) False
  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 an iron nail. Does the bulb glow? (a) No (b) Yes
  40. 40.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) True (b) False

Answer key

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

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