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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 711 · 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. One wire has come loose from the cell. A gap in one wire is bridged by an iron nail. Does the bulb glow? (a) Yes (b) No
  2. 2.True or false: if the switch is OFF, the circuit is closed and current flows. (a) False (b) True
  3. 3.🔁 What must there be for a current to flow? (a) a plastic gap (b) a complete loop (c) a broken path (d) one loose end
  4. 4.True or false: if all wires are joined, the circuit is closed and current flows. (a) False (b) True
  5. 5.True or false: if a wire has come loose, the circuit is open and no current flows. (a) False (b) True
  6. 6.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the base (c) the switch (d) the filament
  7. 7.True or false: if a wire is cut, the circuit is open and no current flows. (a) False (b) True
  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. A gap in one wire is bridged by a steel spoon. Does the bulb glow? (a) Yes (b) No
  9. 9.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) False (b) True
  10. 10.True or false: if a cell is taken out, the circuit is closed and current flows. (a) False (b) True
  11. 11.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
  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 graphite rod. Does the bulb glow? (a) No (b) Yes
  13. 13.🔁 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
  14. 14.True or false: if the loop is complete, the circuit is open and no current flows. (a) False (b) True
  15. 15.🔦 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
  16. 16.True or false: if the loop is complete, the circuit is closed and current flows. (a) True (b) False
  17. 17.🔁 What do we call a circuit with a break in it? (a) a full circuit (b) a series circuit (c) a closed circuit (d) an open circuit
  18. 18.🔦 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) Yes (b) No
  19. 19.Which of these means the circuit is open? (a) all wires are joined (b) the loop is complete (c) a wire has come loose (d) the switch is ON
  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 a glass marble. Does the bulb glow? (a) Yes (b) No
  21. 21.🔦 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
  22. 22.🔦 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 safety pin. Does the bulb glow? (a) Yes (b) No
  23. 23.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
  24. 24.Which of these means the circuit is closed? (a) the switch is OFF (b) a wire has come loose (c) the switch is ON (d) the bulb is unscrewed
  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) No (b) Yes
  26. 26.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
  27. 27.Which of these means the circuit is open? (a) the switch is ON (b) the loop is complete (c) all wires are joined (d) the bulb is unscrewed
  28. 28.Which of these means the circuit is closed? (a) a wire has come loose (b) the switch is OFF (c) all wires are joined (d) a cell is taken out
  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 metal paper clip. Does the bulb glow? (a) Yes (b) No
  30. 30.🔦 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 cotton thread. Does the bulb glow? (a) Yes (b) No
  31. 31.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
  32. 32.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
  33. 33.🔦 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) No (b) Yes
  34. 34.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) the switch is OFF (c) the loop is complete (d) a wire has come loose
  35. 35.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
  36. 36.🔦 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
  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 woollen thread. Does the bulb glow? (a) No (b) Yes
  38. 38.🔦 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 straw. Does the bulb glow? (a) Yes (b) No
  39. 39.🔦 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
  40. 40.True or false: if a wire has come loose, the circuit is closed and current flows. (a) True (b) False

Answer key

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

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