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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 75 · 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) a broken path (c) a plastic gap (d) one loose end
  2. 2.Which of these means the circuit is open? (a) all wires are joined (b) the loop is complete (c) the switch is ON (d) a cell is taken out
  3. 3.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
  4. 4.🔦 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) Yes (b) No
  5. 5.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) it does not matter (b) both of them (c) none (d) only one
  6. 6.True or false: if the switch is ON, the circuit is closed and current flows. (a) True (b) False
  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 aluminium foil. Does the bulb glow? (a) Yes (b) No
  8. 8.🔦 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
  9. 9.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
  10. 10.🔦 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
  11. 11.🔦 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
  12. 12.🔦 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) Yes (b) No
  13. 13.Which of these means the circuit is closed? (a) the switch is OFF (b) a wire has come loose (c) the bulb is unscrewed (d) the switch is ON
  14. 14.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
  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 plastic straw. Does the bulb glow? (a) No (b) Yes
  16. 16.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
  17. 17.True or false: if all wires are joined, the circuit is closed and current flows. (a) False (b) True
  18. 18.True or false: if the loop is complete, the circuit is closed and current flows. (a) True (b) False
  19. 19.🔦 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 cotton thread. Does the bulb glow? (a) Yes (b) No
  20. 20.🔦 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) Yes (b) No
  21. 21.Which of these means the circuit is closed? (a) the switch is OFF (b) a cell is taken out (c) a wire is cut (d) the loop is complete
  22. 22.🔁 What do we call a circuit with a break in it? (a) a series circuit (b) an open circuit (c) a full circuit (d) a closed circuit
  23. 23.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
  24. 24.🔦 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
  25. 25.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
  26. 26.🔦 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
  27. 27.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the base (c) the switch (d) the filament
  28. 28.True or false: if a wire has come loose, the circuit is closed and current flows. (a) False (b) True
  29. 29.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
  30. 30.True or false: if a cell is taken out, the circuit is open and no current flows. (a) False (b) True
  31. 31.🔦 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
  32. 32.🔦 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) Yes (b) No
  33. 33.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
  34. 34.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
  35. 35.🔦 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) No (b) Yes
  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 dry cork. Does the bulb glow? (a) Yes (b) No
  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 rubber eraser. Does the bulb glow? (a) No (b) Yes
  38. 38.🔦 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 woollen thread. Does the bulb glow? (a) Yes (b) No
  39. 39.True or false: if the switch is OFF, the circuit is open and no current flows. (a) True (b) False
  40. 40.True or false: if a wire is cut, the circuit is open and no current flows. (a) False (b) True

Answer key

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

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