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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 940 · 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.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the switch (c) the filament (d) the base
  2. 2.Which of these means the circuit is closed? (a) a cell is taken out (b) the switch is OFF (c) the bulb is unscrewed (d) all wires are joined
  3. 3.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
  4. 4.🔁 What do we call a circuit with a break in it? (a) an open circuit (b) a closed circuit (c) a full circuit (d) a series circuit
  5. 5.🔦 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
  6. 6.🔁 What must there be for a current to flow? (a) a broken path (b) a plastic gap (c) a complete loop (d) one loose end
  7. 7.True or false: if the loop is complete, the circuit is open and no current flows. (a) False (b) True
  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 brass key. Does the bulb glow? (a) No (b) Yes
  9. 9.🔁 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) none (d) both of them
  10. 10.Which of these means the circuit is open? (a) a cell is taken out (b) the loop is complete (c) the switch is ON (d) all wires are joined
  11. 11.True or false: if all wires are joined, the circuit is open and no current flows. (a) False (b) True
  12. 12.True or false: if a cell is taken out, the circuit is open and no current flows. (a) True (b) False
  13. 13.Which of these means the circuit is open? (a) the loop is complete (b) the switch is OFF (c) the switch is ON (d) all wires are joined
  14. 14.Which of these means the circuit is open? (a) a wire has come loose (b) all wires are joined (c) the loop is complete (d) the switch is ON
  15. 15.🔦 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 an iron nail. Does the bulb glow? (a) Yes (b) No
  16. 16.🔦 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) Yes (b) No
  17. 17.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
  18. 18.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) a wire is cut (d) the switch is ON
  19. 19.🔦 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) Yes (b) No
  20. 20.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
  21. 21.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
  22. 22.🔦 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
  23. 23.True or false: if all wires are joined, the circuit is closed and current flows. (a) False (b) True
  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 aluminium foil. Does the bulb glow? (a) No (b) Yes
  25. 25.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
  26. 26.True or false: if a wire has come loose, the circuit is closed and current flows. (a) True (b) False
  27. 27.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) the switch is OFF (c) a wire is cut (d) the switch is ON
  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 plastic straw. Does the bulb glow? (a) Yes (b) No
  29. 29.🔦 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
  30. 30.🔦 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 glass marble. Does the bulb glow? (a) No (b) Yes
  31. 31.🔦 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 band. 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 rubber eraser. Does the bulb glow? (a) Yes (b) No
  33. 33.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) False (b) True
  34. 34.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
  35. 35.🔦 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) No (b) Yes
  36. 36.True or false: if a wire has come loose, the circuit is open and no current flows. (a) True (b) False
  37. 37.🔦 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 dry cork. Does the bulb glow? (a) Yes (b) No
  38. 38.🔦 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 an iron nail. Does the bulb glow? (a) No (b) Yes
  39. 39.🔦 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
  40. 40.Which of these means the circuit is closed? (a) a cell is taken out (b) the bulb is unscrewed (c) the loop is complete (d) a wire has come loose

Answer key

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

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