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Electronics Worksheet: Simple Circuit – Open and Closed

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

Answer key

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

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