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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 438 · 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.True or false: if a wire has come loose, the circuit is open and no current flows. (a) True (b) False
  2. 2.Which of these means the circuit is open? (a) the switch is ON (b) all wires are joined (c) the switch is OFF (d) the loop is complete
  3. 3.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
  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 woollen thread. Does the bulb glow? (a) Yes (b) No
  5. 5.Which of these means the circuit is open? (a) all wires are joined (b) a cell is taken out (c) the loop is complete (d) the switch is ON
  6. 6.🔦 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
  7. 7.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) both of them (b) it does not matter (c) only one (d) none
  8. 8.True or false: if the loop is complete, the circuit is closed and current flows. (a) False (b) True
  9. 9.🔦 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 steel coin. Does the bulb glow? (a) No (b) Yes
  10. 10.True or false: if the loop is complete, the circuit is open and no current flows. (a) True (b) False
  11. 11.Which of these means the circuit is open? (a) the switch is ON (b) all wires are joined (c) the loop is complete (d) the bulb is unscrewed
  12. 12.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the switch (c) the base (d) the filament
  13. 13.Which of these means the circuit is closed? (a) the switch is OFF (b) a cell is taken out (c) the switch is ON (d) a wire has come loose
  14. 14.🔦 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
  15. 15.🔁 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
  16. 16.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
  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 wooden stick. Does the bulb glow? (a) Yes (b) No
  18. 18.🔦 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
  19. 19.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
  20. 20.🔁 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
  21. 21.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) True (b) False
  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 plastic ruler. Does the bulb glow? (a) No (b) Yes
  23. 23.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
  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 spoon. Does the bulb glow? (a) No (b) Yes
  25. 25.True or false: if the switch is ON, the circuit is open and no current flows. (a) True (b) False
  26. 26.🔦 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
  27. 27.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
  28. 28.🔦 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) Yes (b) No
  29. 29.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
  30. 30.🔦 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) No (b) Yes
  31. 31.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
  32. 32.Which of these means the circuit is open? (a) all wires are joined (b) a wire has come loose (c) the loop is complete (d) the switch is ON
  33. 33.Which of these means the circuit is open? (a) all wires are joined (b) the switch is ON (c) the loop is complete (d) a wire is cut
  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 copper wire. Does the bulb glow? (a) Yes (b) No
  35. 35.🔦 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 safety pin. Does the bulb glow? (a) Yes (b) No
  36. 36.True or false: if the bulb is unscrewed, 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 rubber band. Does the bulb glow? (a) No (b) Yes
  38. 38.Which of these means the circuit is closed? (a) a cell is taken out (b) all wires are joined (c) the switch is OFF (d) a wire is cut
  39. 39.🔦 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 rubber band. 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 a rubber eraser. Does the bulb glow? (a) Yes (b) No

Answer key

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

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