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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 124 · 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 the loop is complete, the circuit is open and no current flows. (a) False (b) True
  2. 2.🔁 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) none (d) only one
  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 brass key. Does the bulb glow? (a) No (b) Yes
  4. 4.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) False (b) True
  5. 5.True or false: if the loop is complete, the circuit is closed and current flows. (a) False (b) True
  6. 6.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
  7. 7.🔦 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
  8. 8.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
  9. 9.🔁 What do we call a circuit with a break in it? (a) a closed circuit (b) a full circuit (c) an open circuit (d) a series circuit
  10. 10.🔁 What must there be for a current to flow? (a) a complete loop (b) one loose end (c) a broken path (d) a plastic gap
  11. 11.Which of these means the circuit is closed? (a) a wire has come loose (b) the switch is ON (c) a cell is taken out (d) a wire is cut
  12. 12.True or false: if the switch is ON, the circuit is open and no 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 steel coin. Does the bulb glow? (a) No (b) Yes
  14. 14.Which of these means the circuit is closed? (a) the switch is OFF (b) a cell is taken out (c) a wire is cut (d) all wires are joined
  15. 15.🔦 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 plastic ruler. Does the bulb glow? (a) No (b) Yes
  16. 16.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
  17. 17.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
  18. 18.Which of these means the circuit is open? (a) the loop is complete (b) a cell is taken out (c) the switch is ON (d) all wires are joined
  19. 19.True or false: if the switch is OFF, the circuit is open and no current flows. (a) False (b) True
  20. 20.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) a wire has come loose (d) the switch is ON
  21. 21.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
  22. 22.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the switch (b) the base (c) the filament (d) the glass
  23. 23.🔦 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) Yes (b) No
  24. 24.🔦 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
  25. 25.🔦 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
  26. 26.🔦 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 graphite rod. Does the bulb glow? (a) Yes (b) No
  27. 27.True or false: if a wire is cut, the circuit is open and no current flows. (a) False (b) True
  28. 28.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) a cell is taken out (c) a wire is cut (d) the loop is complete
  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 copper wire. Does the bulb glow? (a) Yes (b) No
  30. 30.True or false: if a wire is cut, the circuit is closed and current flows. (a) False (b) True
  31. 31.Which of these means the circuit is open? (a) the switch is ON (b) all wires are joined (c) the bulb is unscrewed (d) the loop is complete
  32. 32.Which of these means the circuit is open? (a) all wires are joined (b) a wire is cut (c) the loop is complete (d) the switch is ON
  33. 33.🔦 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
  34. 34.🔦 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
  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 metal paper clip. Does the bulb glow? (a) No (b) Yes
  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 aluminium foil. Does the bulb glow? (a) No (b) Yes
  37. 37.🔦 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) Yes (b) No
  38. 38.🔦 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
  39. 39.🔦 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) No (b) Yes
  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 cotton thread. Does the bulb glow? (a) Yes (b) No

Answer key

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

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