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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 262 · 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 closed and current flows. (a) True (b) False
  2. 2.Which of these means the circuit is open? (a) all wires are joined (b) the loop is complete (c) the bulb is unscrewed (d) the switch is ON
  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 cotton thread. Does the bulb glow? (a) Yes (b) No
  4. 4.🔦 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
  5. 5.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 has come loose
  6. 6.True or false: if a wire is cut, the circuit is closed and current flows. (a) True (b) False
  7. 7.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the filament (c) the switch (d) the glass
  8. 8.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
  9. 9.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
  10. 10.🔦 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
  11. 11.🔁 What must there be for a current to flow? (a) a complete loop (b) a broken path (c) one loose end (d) a plastic gap
  12. 12.True or false: if the switch is OFF, the circuit is closed and current flows. (a) True (b) False
  13. 13.🔦 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
  14. 14.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
  15. 15.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 switch is ON
  16. 16.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
  17. 17.🔦 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
  18. 18.True or false: if the switch is OFF, the circuit is open and no current flows. (a) True (b) False
  19. 19.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
  20. 20.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
  21. 21.Which of these means the circuit is closed? (a) the loop is complete (b) a wire is cut (c) the bulb is unscrewed (d) a wire has come loose
  22. 22.🔦 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
  23. 23.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) none (b) only one (c) both of them (d) it does not matter
  24. 24.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
  25. 25.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) all wires are joined (c) a wire has come loose (d) the switch is OFF
  26. 26.Which of these means the circuit is open? (a) the loop is complete (b) the switch is ON (c) the switch is OFF (d) all wires are joined
  27. 27.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
  28. 28.Which of these means the circuit is open? (a) the loop is complete (b) the switch is ON (c) a cell is taken out (d) all wires are joined
  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 is cut
  30. 30.🔦 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
  31. 31.True or false: if the switch is ON, the circuit is open and no current flows. (a) True (b) False
  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) No (b) Yes
  33. 33.🔦 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 metal paper clip. Does the bulb glow? (a) No (b) Yes
  34. 34.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
  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 dry cork. 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. 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
  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 copper wire. Does the bulb glow? (a) Yes (b) No
  38. 38.🔦 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 graphite rod. Does the bulb glow? (a) Yes (b) No
  39. 39.🔦 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 paper strip. Does the bulb glow? (a) No (b) Yes
  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 cotton thread. Does the bulb glow? (a) Yes (b) No

Answer key

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

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