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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 545 · 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. 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
  2. 2.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
  3. 3.Which of these means the circuit is open? (a) all wires are joined (b) the loop is complete (c) the switch is ON (d) the bulb is unscrewed
  4. 4.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
  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 dry cork. Does the bulb glow? (a) Yes (b) No
  6. 6.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) only one (b) none (c) both of them (d) it does not matter
  7. 7.True or false: if the loop is complete, the circuit is closed and current flows. (a) True (b) False
  8. 8.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
  9. 9.True or false: if all wires are joined, the circuit is closed and current flows. (a) True (b) False
  10. 10.🔁 What must there be for a current to flow? (a) a broken path (b) one loose end (c) a complete loop (d) a plastic gap
  11. 11.🔦 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 woollen thread. Does the bulb glow? (a) Yes (b) No
  12. 12.True or false: if the switch is OFF, the circuit is open and no current flows. (a) False (b) True
  13. 13.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
  14. 14.🔦 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 spoon. Does the bulb glow? (a) Yes (b) No
  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. 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. One wire has come loose from the cell. 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 steel spoon. Does the bulb glow? (a) Yes (b) No
  19. 19.🔁 Is the circuit closed or open if a cell is taken out? (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. A gap in one wire is bridged by a plastic ruler. Does the bulb glow? (a) Yes (b) No
  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 graphite rod. Does the bulb glow? (a) No (b) Yes
  22. 22.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
  23. 23.Which of these means the circuit is closed? (a) all wires are joined (b) a cell is taken out (c) the bulb is unscrewed (d) a wire is cut
  24. 24.True or false: if a wire is cut, the circuit is closed and current flows. (a) True (b) False
  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. Does the bulb glow? (a) Yes (b) No
  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 a ceramic cup. Does the bulb glow? (a) No (b) Yes
  27. 27.🔦 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 wooden stick. Does the bulb glow? (a) No (b) Yes
  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 a dry cork. Does the bulb glow? (a) No (b) Yes
  29. 29.🔦 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) No (b) Yes
  30. 30.True or false: if the switch is OFF, the circuit is closed and current flows. (a) True (b) False
  31. 31.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the switch (b) the base (c) the filament (d) the glass
  32. 32.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
  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 steel coin. Does the bulb glow? (a) Yes (b) No
  34. 34.🔁 Is the circuit closed or open if all wires are joined? (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 cotton thread. 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 plastic straw. Does the bulb glow? (a) No (b) Yes
  37. 37.Which of these means the circuit is open? (a) all wires are joined (b) the switch is ON (c) a cell is taken out (d) the loop is complete
  38. 38.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
  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 aluminium foil. Does the bulb glow? (a) No (b) Yes
  40. 40.🔦 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

Answer key

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

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