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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 802 · 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 a cell is taken out, the circuit is open and no current flows. (a) True (b) False
  2. 2.🔁 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
  3. 3.True or false: if the switch is OFF, the circuit is closed and current flows. (a) True (b) False
  4. 4.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
  5. 5.🔦 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
  6. 6.🔦 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
  7. 7.🔦 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 ruler. Does the bulb glow? (a) Yes (b) No
  8. 8.🔦 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
  9. 9.🔦 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) Yes (b) No
  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 plastic straw. Does the bulb glow? (a) No (b) Yes
  11. 11.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
  12. 12.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
  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 safety pin. Does the bulb glow? (a) No (b) Yes
  14. 14.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) the switch is OFF (d) the switch is ON
  15. 15.🔦 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
  16. 16.🔦 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
  17. 17.Which of these means the circuit is closed? (a) a wire is cut (b) a cell is taken out (c) a wire has come loose (d) all wires are joined
  18. 18.True or false: if the switch is ON, the circuit is open and no current flows. (a) True (b) False
  19. 19.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the switch (c) the base (d) the filament
  20. 20.🔦 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
  21. 21.🔦 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
  22. 22.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
  23. 23.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
  24. 24.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) a wire has come loose (c) the switch is OFF (d) the loop is complete
  25. 25.🔦 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
  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 glass marble. Does the bulb glow? (a) Yes (b) No
  27. 27.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) a cell is taken out (d) the switch is ON
  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 is cut
  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 brass key. Does the bulb glow? (a) Yes (b) No
  30. 30.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
  31. 31.True or false: if all wires are joined, the circuit is closed and current flows. (a) True (b) False
  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 steel spoon. Does the bulb glow? (a) Yes (b) No
  33. 33.🔦 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
  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 metal paper clip. Does the bulb glow? (a) Yes (b) No
  35. 35.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
  36. 36.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
  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 rubber eraser. Does the bulb glow? (a) Yes (b) No
  38. 38.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
  39. 39.True or false: if a wire has come loose, the circuit is closed and current flows. (a) False (b) True
  40. 40.🔁 What do we call a circuit with a break in it? (a) an open circuit (b) a full circuit (c) a series circuit (d) a closed circuit

Answer key

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

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