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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 467 · 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.🔁 What do we call a circuit with a break in it? (a) a closed circuit (b) a full circuit (c) an open circuit (d) a series circuit
  2. 2.Which of these means the circuit is open? (a) a cell is taken out (b) the switch is ON (c) all wires are joined (d) the loop is complete
  3. 3.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the filament (c) the switch (d) the base
  4. 4.🔦 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
  5. 5.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
  6. 6.🔦 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
  7. 7.True or false: if a wire has come loose, the circuit is closed and 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. Does the bulb glow? (a) Yes (b) No
  9. 9.True or false: if all wires are joined, the circuit is closed and current flows. (a) False (b) True
  10. 10.Which of these means the circuit is closed? (a) a wire is cut (b) a wire has come loose (c) a cell is taken out (d) all wires are joined
  11. 11.🔁 What must there be for a current to flow? (a) a complete loop (b) a broken path (c) a plastic gap (d) one loose end
  12. 12.🔦 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
  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 rubber band. Does the bulb glow? (a) No (b) Yes
  14. 14.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
  15. 15.🔦 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 ruler. Does the bulb glow? (a) Yes (b) No
  16. 16.Which of these means the circuit is closed? (a) a wire has come loose (b) the bulb is unscrewed (c) the switch is ON (d) the switch is OFF
  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 steel coin. Does the bulb glow? (a) No (b) Yes
  18. 18.True or false: if the switch is OFF, the circuit is closed and current flows. (a) True (b) False
  19. 19.Which of these means the circuit is open? (a) the switch is ON (b) a wire is cut (c) the loop is complete (d) all wires are joined
  20. 20.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
  21. 21.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
  22. 22.True or false: if the loop is complete, the circuit is open and no current flows. (a) False (b) True
  23. 23.🔦 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
  24. 24.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) the loop is complete (c) a wire has come loose (d) a cell is taken out
  25. 25.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
  26. 26.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
  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 cotton thread. 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) True (b) False
  29. 29.True or false: if a wire is cut, the circuit is closed and current flows. (a) True (b) False
  30. 30.🔦 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 glass marble. Does the bulb glow? (a) Yes (b) No
  31. 31.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
  32. 32.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) it does not matter (b) none (c) only one (d) both of them
  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 paper strip. Does the bulb glow? (a) Yes (b) No
  34. 34.True or false: if the loop is complete, the circuit is closed and current flows. (a) True (b) False
  35. 35.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
  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 aluminium foil. Does the bulb glow? (a) No (b) Yes
  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 dry cork. Does the bulb glow? (a) No (b) Yes
  38. 38.🔦 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 dry cork. Does the bulb glow? (a) No (b) Yes
  39. 39.🔦 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
  40. 40.🔦 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 an iron nail. Does the bulb glow? (a) No (b) Yes

Answer key

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

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