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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 768 · 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.True or false: if a wire has come loose, the circuit is closed and current flows. (a) True (b) False
  2. 2.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
  3. 3.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
  4. 4.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
  5. 5.🔦 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 paper strip. Does the bulb glow? (a) No (b) Yes
  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) Yes (b) No
  7. 7.🔁 What must there be for a current to flow? (a) one loose end (b) a plastic gap (c) a complete loop (d) a broken path
  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 paper strip. Does the bulb glow? (a) Yes (b) No
  9. 9.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) none (b) both of them (c) only one (d) it does not matter
  10. 10.True or false: if a cell is taken out, the circuit is open and no current flows. (a) False (b) True
  11. 11.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
  12. 12.🔦 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
  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. Does the bulb glow? (a) Yes (b) No
  14. 14.Which of these means the circuit is closed? (a) the switch is OFF (b) the switch is ON (c) a cell is taken out (d) a wire is cut
  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 dry cork. Does the bulb glow? (a) Yes (b) No
  16. 16.Which of these means the circuit is open? (a) the switch is ON (b) the loop is complete (c) all wires are joined (d) a cell is taken out
  17. 17.Which of these means the circuit is closed? (a) the switch is OFF (b) the bulb is unscrewed (c) a cell is taken out (d) all wires are joined
  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 metal paper clip. Does the bulb glow? (a) No (b) Yes
  19. 19.True or false: if the switch is OFF, the circuit is open and no current flows. (a) False (b) True
  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 woollen thread. Does the bulb glow? (a) Yes (b) No
  21. 21.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) False (b) True
  22. 22.True or false: if the loop is complete, the circuit is closed and 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. Does the bulb glow? (a) No (b) Yes
  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 graphite rod. Does the bulb glow? (a) Yes (b) No
  25. 25.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
  26. 26.🔦 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) 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. Does the bulb glow? (a) Yes (b) No
  28. 28.True or false: if a wire has come loose, the circuit is open and no current flows. (a) False (b) True
  29. 29.🔁 What do we call a circuit with a break in it? (a) a series circuit (b) an open circuit (c) a closed circuit (d) a full circuit
  30. 30.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
  31. 31.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the switch (b) the base (c) the glass (d) the filament
  32. 32.True or false: if a wire is cut, the circuit is closed and current flows. (a) True (b) False
  33. 33.Which of these means the circuit is open? (a) the switch is ON (b) the switch is OFF (c) all wires are joined (d) the loop is complete
  34. 34.🔦 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 dry cork. Does the bulb glow? (a) No (b) Yes
  35. 35.True or false: if all wires are joined, the circuit is closed and current flows. (a) True (b) False
  36. 36.🔦 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 steel coin. Does the bulb glow? (a) Yes (b) No
  37. 37.🔦 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
  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 ceramic cup. 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. All the wires are firmly joined. A gap in one wire is bridged by a paper strip. Does the bulb glow? (a) Yes (b) No
  40. 40.🔦 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 an iron nail. Does the bulb glow? (a) Yes (b) No

Answer key

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

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