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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 734 · 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.🔦 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
  2. 2.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) the switch is OFF (d) the switch is ON
  3. 3.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) only one (b) it does not matter (c) none (d) both of them
  4. 4.🔦 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 straw. Does the bulb glow? (a) No (b) Yes
  5. 5.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
  6. 6.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
  7. 7.🔁 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
  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.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) the switch is ON (d) the bulb is unscrewed
  10. 10.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) the switch is OFF (c) a wire has come loose (d) the loop is complete
  11. 11.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 cell is taken out
  12. 12.True or false: if a wire is cut, the circuit is open and no current flows. (a) False (b) True
  13. 13.True or false: if a wire has come loose, 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 dry cork. Does the bulb glow? (a) No (b) Yes
  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 copper wire. Does the bulb glow? (a) No (b) Yes
  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 an iron nail. Does the bulb glow? (a) Yes (b) No
  17. 17.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
  18. 18.True or false: if all wires are joined, 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 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
  20. 20.🔦 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) No (b) Yes
  21. 21.🔦 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) 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 paper strip. Does the bulb glow? (a) No (b) Yes
  23. 23.🔦 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 aluminium foil. Does the bulb glow? (a) No (b) Yes
  24. 24.True or false: if the switch is OFF, the circuit is open and no current flows. (a) True (b) False
  25. 25.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the glass (c) the switch (d) the filament
  26. 26.🔦 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
  27. 27.Which of these means the circuit is closed? (a) the switch is OFF (b) the bulb is unscrewed (c) a wire has come loose (d) all wires are joined
  28. 28.🔦 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
  29. 29.Which of these means the circuit is open? (a) the switch is ON (b) the loop is complete (c) all wires are joined (d) a wire has come loose
  30. 30.True or false: if a cell is taken out, the circuit is open and no current flows. (a) True (b) False
  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 cotton thread. Does the bulb glow? (a) Yes (b) No
  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. Does the bulb glow? (a) Yes (b) No
  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 steel coin. Does the bulb glow? (a) Yes (b) No
  34. 34.🔁 What do we call a circuit with a break in it? (a) a full circuit (b) an open circuit (c) a series circuit (d) a closed circuit
  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 plastic straw. 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. One wire has come loose from the cell. A gap in one wire is bridged by a copper wire. Does the bulb glow? (a) Yes (b) No
  37. 37.Which of these means the circuit is open? (a) the switch is ON (b) a wire is cut (c) all wires are joined (d) the loop is complete
  38. 38.True or false: if the loop is complete, the circuit is open and no current flows. (a) False (b) True
  39. 39.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
  40. 40.🔦 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 steel coin. Does the bulb glow? (a) No (b) Yes

Answer key

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

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