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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 867 · 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.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
  2. 2.True or false: if the loop is complete, the circuit is open and no current flows. (a) True (b) False
  3. 3.🔦 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 ceramic cup. Does the bulb glow? (a) No (b) Yes
  4. 4.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the switch (c) the glass (d) the filament
  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 a graphite rod. Does the bulb glow? (a) Yes (b) No
  6. 6.🔁 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
  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 a brass key. Does the bulb glow? (a) Yes (b) No
  8. 8.🔦 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
  9. 9.Which of these means the circuit is closed? (a) the switch is OFF (b) the switch is ON (c) a cell is taken out (d) a wire has come loose
  10. 10.True or false: if a cell is taken out, the circuit is closed and current flows. (a) True (b) False
  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 paper strip. Does the bulb glow? (a) Yes (b) No
  12. 12.True or false: if a wire has come loose, the circuit is open and no current flows. (a) False (b) True
  13. 13.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
  14. 14.True or false: if a wire is cut, the circuit is open and no current flows. (a) True (b) False
  15. 15.🔦 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
  16. 16.🔦 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
  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 woollen thread. Does the bulb glow? (a) Yes (b) No
  18. 18.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
  19. 19.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
  20. 20.🔦 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
  21. 21.🔦 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 steel spoon. Does the bulb glow? (a) Yes (b) No
  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 steel coin. Does the bulb glow? (a) Yes (b) No
  23. 23.Which of these means the circuit is closed? (a) a wire has come loose (b) the switch is OFF (c) a cell is taken out (d) the loop is complete
  24. 24.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
  25. 25.🔦 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 aluminium foil. Does the bulb glow? (a) No (b) Yes
  26. 26.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
  27. 27.True or false: if all wires are joined, the circuit is closed and current flows. (a) False (b) True
  28. 28.🔁 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
  29. 29.🔦 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 cotton thread. Does the bulb glow? (a) Yes (b) No
  30. 30.Which of these means the circuit is closed? (a) all wires are joined (b) a wire is cut (c) a wire has come loose (d) a cell is taken out
  31. 31.True or false: if the loop is complete, the circuit is closed and current flows. (a) False (b) True
  32. 32.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
  33. 33.🔦 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 glass marble. Does the bulb glow? (a) Yes (b) No
  34. 34.🔦 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 plastic straw. Does the bulb glow? (a) No (b) Yes
  35. 35.🔦 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
  36. 36.🔦 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 ceramic cup. Does the bulb glow? (a) Yes (b) No
  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 wooden stick. Does the bulb glow? (a) No (b) Yes
  38. 38.True or false: if a wire has come loose, the circuit is closed and current flows. (a) True (b) False
  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 metal paper clip. Does the bulb glow? (a) No (b) Yes
  40. 40.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) none (b) only one (c) it does not matter (d) both of them

Answer key

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

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