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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 147 · 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 the switch is OFF, the circuit is open and no current flows. (a) False (b) True
  2. 2.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) a cell is taken out (c) the switch is OFF (d) the switch is ON
  3. 3.True or false: if a cell is taken out, the circuit is closed and current flows. (a) True (b) False
  4. 4.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) only one (b) it does not matter (c) both of them (d) none
  5. 5.🔦 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
  6. 6.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
  7. 7.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
  8. 8.🔦 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
  9. 9.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
  10. 10.🔁 What must there be for a current to flow? (a) one loose end (b) a broken path (c) a complete loop (d) a plastic gap
  11. 11.🔦 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 dry cork. Does the bulb glow? (a) No (b) Yes
  12. 12.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
  13. 13.🔦 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) Yes (b) No
  14. 14.🔦 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
  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. Does the bulb glow? (a) No (b) Yes
  17. 17.True or false: if a cell is taken out, the circuit is open and no current flows. (a) False (b) True
  18. 18.🔦 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 paper strip. Does the bulb glow? (a) Yes (b) No
  19. 19.🔦 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
  20. 20.True or false: if a wire is cut, the circuit is open and no current flows. (a) False (b) True
  21. 21.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
  22. 22.🔦 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
  23. 23.Which of these means the circuit is closed? (a) all wires are joined (b) a wire is cut (c) the switch is OFF (d) a wire has come loose
  24. 24.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the switch (b) the glass (c) the base (d) the filament
  25. 25.🔦 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 spoon. Does the bulb glow? (a) No (b) Yes
  26. 26.True or false: if the switch is OFF, the circuit is closed and current flows. (a) False (b) True
  27. 27.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
  28. 28.Which of these means the circuit is open? (a) the switch is ON (b) all wires are joined (c) the loop is complete (d) the bulb is unscrewed
  29. 29.True or false: if the loop is complete, the circuit is open and no current flows. (a) False (b) True
  30. 30.🔦 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 brass key. Does the bulb glow? (a) No (b) Yes
  31. 31.True or false: if all wires are joined, the circuit is open and no 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 metal paper clip. Does the bulb glow? (a) Yes (b) No
  33. 33.🔦 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) No (b) Yes
  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 plastic ruler. Does the bulb glow? (a) Yes (b) No
  35. 35.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
  36. 36.🔦 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 cotton thread. 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.True or false: if the loop is complete, the circuit is closed and current flows. (a) True (b) False
  39. 39.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
  40. 40.Which of these means the circuit is open? (a) the switch is ON (b) all wires are joined (c) a wire has come loose (d) the loop is complete

Answer key

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

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