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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 705 · 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. Does the bulb glow? (a) No (b) Yes
  2. 2.🔁 What do we call a circuit with a break in it? (a) an open circuit (b) a series circuit (c) a full circuit (d) a closed circuit
  3. 3.True or false: if all wires are joined, the circuit is closed and current flows. (a) False (b) True
  4. 4.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the filament (c) the glass (d) the switch
  5. 5.🔦 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 brass key. Does the bulb glow? (a) No (b) Yes
  6. 6.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) True (b) False
  7. 7.True or false: if the switch is OFF, the circuit is open and no current flows. (a) False (b) True
  8. 8.🔁 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
  9. 9.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) the switch is ON (d) the switch is OFF
  10. 10.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
  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 ceramic cup. Does the bulb glow? (a) Yes (b) No
  12. 12.🔦 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
  13. 13.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
  14. 14.Which of these means the circuit is open? (a) the loop is complete (b) the switch is ON (c) the bulb is unscrewed (d) all wires are joined
  15. 15.Which of these means the circuit is closed? (a) a cell is taken out (b) the loop is complete (c) the switch is OFF (d) a wire has come loose
  16. 16.Which of these means the circuit is open? (a) the loop is complete (b) the switch is ON (c) a wire has come loose (d) all wires are joined
  17. 17.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
  18. 18.True or false: if the switch is ON, the circuit is open and no current flows. (a) True (b) False
  19. 19.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
  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 aluminium foil. Does the bulb glow? (a) Yes (b) No
  21. 21.🔦 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) No (b) Yes
  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 OFF? (a) open (b) closed
  24. 24.🔦 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 aluminium foil. 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 a ceramic cup. Does the bulb glow? (a) No (b) Yes
  26. 26.True or false: if a wire has come loose, the circuit is closed and current flows. (a) False (b) True
  27. 27.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) a wire is cut (c) a cell is taken out (d) the switch is ON
  28. 28.🔦 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
  29. 29.🔦 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
  30. 30.True or false: if the loop is complete, the circuit is open and no current flows. (a) False (b) True
  31. 31.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) both of them (b) only one (c) it does not matter (d) none
  32. 32.🔦 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
  33. 33.🔦 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
  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 copper wire. Does the bulb glow? (a) No (b) Yes
  35. 35.True or false: if a wire is cut, the circuit is open and no current flows. (a) False (b) True
  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 wooden stick. Does the bulb glow? (a) Yes (b) No
  37. 37.🔦 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) No (b) Yes
  38. 38.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 cell is taken out
  39. 39.True or false: if a wire is cut, the circuit is closed and current flows. (a) False (b) True
  40. 40.True or false: if the switch is ON, the circuit is closed and current flows. (a) True (b) False

Answer key

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

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