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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 127 · 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 all wires are joined, the circuit is open and no current flows. (a) True (b) False
  2. 2.🔦 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
  3. 3.Which of these means the circuit is open? (a) the loop is complete (b) the switch is OFF (c) the switch is ON (d) all wires are joined
  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 cotton thread. Does the bulb glow? (a) No (b) Yes
  5. 5.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the filament (b) the switch (c) the glass (d) the base
  6. 6.🔦 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 eraser. Does the bulb glow? (a) No (b) Yes
  7. 7.🔦 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
  8. 8.🔦 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
  9. 9.True or false: if all wires are joined, the circuit is closed and current flows. (a) False (b) True
  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 wooden stick. Does the bulb glow? (a) Yes (b) No
  11. 11.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
  12. 12.🔦 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 steel spoon. Does the bulb glow? (a) No (b) Yes
  13. 13.True or false: if a cell is taken out, the circuit is closed and current flows. (a) True (b) False
  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 copper wire. Does the bulb glow? (a) Yes (b) No
  15. 15.Which of these means the circuit is closed? (a) a wire has come loose (b) a cell is taken out (c) all wires are joined (d) the bulb is unscrewed
  16. 16.🔁 What do we call a circuit with a break in it? (a) a series circuit (b) a closed circuit (c) an open circuit (d) a full circuit
  17. 17.Which of these means the circuit is open? (a) the loop is complete (b) a wire has come loose (c) the switch is ON (d) all wires are joined
  18. 18.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) only one (b) both of them (c) it does not matter (d) none
  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 glass marble. Does the bulb glow? (a) Yes (b) No
  20. 20.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
  21. 21.🔦 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 woollen thread. Does the bulb glow? (a) Yes (b) No
  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.True or false: if a wire has come loose, the circuit is open and no current flows. (a) True (b) False
  24. 24.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
  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. A gap in one wire is bridged by a dry cork. Does the bulb glow? (a) No (b) Yes
  26. 26.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
  27. 27.🔦 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) Yes (b) No
  28. 28.🔦 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 spoon. Does the bulb glow? (a) Yes (b) No
  29. 29.Which of these means the circuit is open? (a) a wire is cut (b) the switch is ON (c) all wires are joined (d) the loop is complete
  30. 30.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) False (b) True
  31. 31.True or false: if the switch is ON, the circuit is open and no current flows. (a) True (b) False
  32. 32.Which of these means the circuit is open? (a) the switch is ON (b) the loop is complete (c) the bulb is unscrewed (d) all wires are joined
  33. 33.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
  34. 34.🔦 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 wooden stick. Does the bulb glow? (a) No (b) Yes
  35. 35.🔦 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 band. Does the bulb glow? (a) No (b) Yes
  36. 36.True or false: if the switch is ON, the circuit is closed and current flows. (a) True (b) False
  37. 37.Which of these means the circuit is closed? (a) a wire has come loose (b) the loop is complete (c) a cell is taken out (d) a wire is cut
  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 rubber eraser. Does the bulb glow? (a) Yes (b) No
  39. 39.True or false: if a wire is cut, the circuit is open and no current flows. (a) False (b) True
  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 glass marble. Does the bulb glow? (a) No (b) Yes

Answer key

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

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