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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 49 · 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.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the base (c) the filament (d) the switch
  2. 2.Which of these means the circuit is closed? (a) a cell is taken out (b) a wire is cut (c) the loop is complete (d) the switch is OFF
  3. 3.🔁 What do we call a circuit with a break in it? (a) a series circuit (b) a closed circuit (c) a full circuit (d) an open circuit
  4. 4.🔦 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 plastic straw. Does the bulb glow? (a) Yes (b) No
  5. 5.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
  6. 6.Which of these means the circuit is open? (a) the bulb is unscrewed (b) all wires are joined (c) the switch is ON (d) the loop is complete
  7. 7.Which of these means the circuit is closed? (a) a wire is cut (b) a cell is taken out (c) all wires are joined (d) the switch is OFF
  8. 8.🔦 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 aluminium foil. Does the bulb glow? (a) No (b) Yes
  9. 9.🔦 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 rubber eraser. Does the bulb glow? (a) Yes (b) No
  10. 10.🔦 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 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) closed (b) open
  12. 12.Which of these means the circuit is open? (a) the switch is OFF (b) the switch is ON (c) the loop is complete (d) all wires are joined
  13. 13.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
  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 safety pin. Does the bulb glow? (a) Yes (b) No
  15. 15.True or false: if a cell is taken out, the circuit is closed and current flows. (a) False (b) True
  16. 16.🔦 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
  17. 17.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
  18. 18.🔦 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
  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 steel spoon. Does the bulb glow? (a) Yes (b) No
  20. 20.🔦 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) Yes (b) No
  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 rubber eraser. 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 brass key. Does the bulb glow? (a) Yes (b) No
  23. 23.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
  24. 24.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
  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 dry cork. Does the bulb glow? (a) Yes (b) No
  26. 26.🔦 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
  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) No (b) Yes
  28. 28.Which of these means the circuit is open? (a) all wires are joined (b) the loop is complete (c) the switch is ON (d) a wire has come loose
  29. 29.True or false: if all wires are joined, the circuit is open and no current flows. (a) False (b) True
  30. 30.🔁 What must there be for a current to flow? (a) one loose end (b) a complete loop (c) a broken path (d) a plastic gap
  31. 31.Which of these means the circuit is open? (a) all wires are joined (b) a cell is taken out (c) the loop is complete (d) the switch is ON
  32. 32.True or false: if a wire is cut, the circuit is open and no current flows. (a) True (b) False
  33. 33.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) True (b) False
  34. 34.🔦 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 wooden stick. Does the bulb glow? (a) No (b) Yes
  35. 35.🔦 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
  36. 36.True or false: if the switch is ON, the circuit is closed and current flows. (a) True (b) False
  37. 37.🔦 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 band. Does the bulb glow? (a) Yes (b) No
  38. 38.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) it does not matter (b) only one (c) none (d) both of them
  39. 39.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
  40. 40.True or false: if a wire has come loose, the circuit is closed and current flows. (a) False (b) True

Answer key

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

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