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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 33 · 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 filament (b) the glass (c) the base (d) the switch
  2. 2.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
  3. 3.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) a wire has come loose (c) the switch is ON (d) the switch is OFF
  4. 4.🔁 What do we call a circuit with a break in it? (a) a full circuit (b) a series circuit (c) an open circuit (d) a closed circuit
  5. 5.🔦 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
  6. 6.True or false: if the switch is OFF, the circuit is closed and current flows. (a) False (b) True
  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 metal paper clip. Does the bulb glow? (a) No (b) Yes
  8. 8.True or false: if a wire has come loose, the circuit is closed and current flows. (a) False (b) True
  9. 9.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) only one (b) none (c) it does not matter (d) both of them
  10. 10.True or false: if a cell is taken out, the circuit is open and no current flows. (a) False (b) True
  11. 11.🔦 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 metal paper clip. Does the bulb glow? (a) No (b) Yes
  12. 12.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
  13. 13.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
  14. 14.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
  15. 15.True or false: if a wire is cut, the circuit is closed and current flows. (a) True (b) False
  16. 16.🔦 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 plastic straw. 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. 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
  18. 18.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
  19. 19.Which of these means the circuit is closed? (a) a cell is taken out (b) the bulb is unscrewed (c) a wire is cut (d) all wires are joined
  20. 20.🔁 Is the circuit closed or open if a wire has come loose? (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 safety pin. 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. A gap in one wire is bridged by a safety pin. Does the bulb glow? (a) Yes (b) No
  23. 23.🔦 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 copper wire. Does the bulb glow? (a) Yes (b) No
  24. 24.True or false: if a wire is cut, the circuit is open and no current flows. (a) True (b) False
  25. 25.True or false: if all wires are joined, the circuit is closed and current flows. (a) False (b) True
  26. 26.🔦 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
  27. 27.🔦 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 dry cork. Does the bulb glow? (a) No (b) Yes
  28. 28.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
  29. 29.Which of these means the circuit is open? (a) the loop is complete (b) the switch is ON (c) the switch is OFF (d) all wires are joined
  30. 30.True or false: if the loop is complete, the circuit is open and no current flows. (a) False (b) True
  31. 31.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) a cell is taken out (c) the switch is OFF (d) the loop is complete
  32. 32.🔦 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
  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 brass key. Does the bulb glow? (a) Yes (b) No
  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 cotton thread. Does the bulb glow? (a) No (b) Yes
  35. 35.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
  36. 36.True or false: if the switch is ON, the circuit is open and no current flows. (a) True (b) False
  37. 37.🔦 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 an iron nail. Does the bulb glow? (a) No (b) Yes
  38. 38.🔦 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
  39. 39.🔦 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 an iron nail. Does the bulb glow? (a) Yes (b) No
  40. 40.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

Answer key

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

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