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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 753 · 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 cell is taken out, the circuit is closed and current flows. (a) True (b) False
  2. 2.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
  3. 3.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) it does not matter (b) only one (c) both of them (d) none
  4. 4.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) the switch is OFF (c) the switch is ON (d) a cell is taken out
  5. 5.🔦 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) Yes (b) No
  6. 6.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
  7. 7.Which of these means the circuit is closed? (a) the loop is complete (b) the switch is OFF (c) a wire is cut (d) a wire has come loose
  8. 8.🔁 What must there be for a current to flow? (a) one loose end (b) a plastic gap (c) a broken path (d) a complete loop
  9. 9.🔦 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
  10. 10.🔁 What do we call a circuit with a break in it? (a) a full circuit (b) a closed circuit (c) a series circuit (d) an open circuit
  11. 11.Which of these means the circuit is open? (a) the switch is OFF (b) all wires are joined (c) the loop is complete (d) the switch is ON
  12. 12.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
  13. 13.Which of these means the circuit is closed? (a) a cell is taken out (b) a wire has come loose (c) all wires are joined (d) the bulb is unscrewed
  14. 14.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
  15. 15.🔦 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
  16. 16.🔦 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
  17. 17.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
  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 brass key. Does the bulb glow? (a) No (b) Yes
  19. 19.🔦 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
  20. 20.Which of these means the circuit is open? (a) all wires are joined (b) a wire has come loose (c) the loop is complete (d) the switch is ON
  21. 21.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) the switch is ON (d) a wire is cut
  22. 22.🔦 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) No (b) Yes
  23. 23.True or false: if the switch is ON, the circuit is closed and current flows. (a) True (b) False
  24. 24.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) True (b) False
  25. 25.True or false: if the switch is OFF, the circuit is closed and current flows. (a) False (b) True
  26. 26.🔦 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
  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 dry cork. Does the bulb glow? (a) No (b) Yes
  29. 29.True or false: if the loop is complete, the circuit is open and no current flows. (a) True (b) False
  30. 30.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
  31. 31.🔦 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 aluminium foil. Does the bulb glow? (a) Yes (b) No
  32. 32.🔦 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 glass marble. Does the bulb glow? (a) Yes (b) No
  33. 33.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the switch (c) the glass (d) the filament
  34. 34.True or false: if a cell is taken out, the circuit is open and no current flows. (a) False (b) True
  35. 35.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
  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 steel coin. Does the bulb glow? (a) Yes (b) No
  37. 37.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
  38. 38.🔦 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) Yes (b) No
  39. 39.🔦 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
  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. Does the bulb glow? (a) Yes (b) No

Answer key

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

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