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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 976 · 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 the loop is complete? (a) open (b) closed
  2. 2.🔦 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) No (b) Yes
  3. 3.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) the switch is ON (c) a wire has come loose (d) a wire is cut
  4. 4.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
  5. 5.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) True (b) False
  6. 6.🔦 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
  7. 7.True or false: if a wire is cut, 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. A gap in one wire is bridged by a graphite rod. Does the bulb glow? (a) Yes (b) No
  9. 9.True or false: if all wires are joined, the circuit is closed and current flows. (a) False (b) True
  10. 10.🔦 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 safety pin. Does the bulb glow? (a) No (b) Yes
  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. Does the bulb glow? (a) No (b) Yes
  12. 12.🔦 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
  13. 13.True or false: if the switch is OFF, the circuit is open and no current flows. (a) False (b) True
  14. 14.🔦 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
  15. 15.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
  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 rubber band. Does the bulb glow? (a) No (b) Yes
  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 bulb is unscrewed? (a) open (b) closed
  19. 19.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
  20. 20.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
  21. 21.🔁 What must there be for a current to flow? (a) a broken path (b) a complete loop (c) a plastic gap (d) one loose end
  22. 22.True or false: if the switch is ON, the circuit is closed and current flows. (a) False (b) True
  23. 23.Which of these means the circuit is closed? (a) a cell is taken out (b) the switch is OFF (c) all wires are joined (d) a wire has come loose
  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 a steel coin. 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. A gap in one wire is bridged by a safety pin. Does the bulb glow? (a) Yes (b) No
  26. 26.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
  27. 27.🔦 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) No (b) Yes
  28. 28.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
  29. 29.🔁 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
  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 graphite rod. Does the bulb glow? (a) Yes (b) No
  31. 31.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the filament (c) the base (d) the switch
  32. 32.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
  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 paper strip. Does the bulb glow? (a) No (b) Yes
  34. 34.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
  35. 35.Which of these means the circuit is open? (a) the switch is ON (b) all wires are joined (c) the loop is complete (d) a cell is taken out
  36. 36.🔦 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
  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 glass marble. Does the bulb glow? (a) Yes (b) No
  38. 38.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) both of them (b) none (c) it does not matter (d) only one
  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 rubber eraser. Does the bulb glow? (a) Yes (b) No
  40. 40.🔦 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

Answer key

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

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