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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 37 · 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 must there be for a current to flow? (a) a plastic gap (b) a broken path (c) a complete loop (d) one loose end
  2. 2.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
  3. 3.Which of these means the circuit is open? (a) the switch is ON (b) all wires are joined (c) the loop is complete (d) the switch is OFF
  4. 4.🔦 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) No (b) Yes
  5. 5.🔁 What do we call a circuit with a break in it? (a) a series circuit (b) a full circuit (c) a closed circuit (d) an open circuit
  6. 6.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the switch (c) the filament (d) the base
  7. 7.True or false: if the switch is ON, the circuit is closed and current flows. (a) True (b) False
  8. 8.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
  9. 9.Which of these means the circuit is closed? (a) the loop is complete (b) a wire is cut (c) the bulb is unscrewed (d) a wire has come loose
  10. 10.True or false: if a wire has come loose, the circuit is closed and current flows. (a) True (b) False
  11. 11.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
  12. 12.True or false: if the switch is OFF, the circuit is open and no current flows. (a) True (b) False
  13. 13.🔦 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
  14. 14.🔦 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
  15. 15.True or false: if a wire has come loose, the circuit is open and no current flows. (a) True (b) False
  16. 16.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
  17. 17.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) none (b) it does not matter (c) both of them (d) only one
  18. 18.True or false: if a wire is cut, the circuit is open and no current flows. (a) True (b) False
  19. 19.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
  20. 20.🔦 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
  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 steel coin. Does the bulb glow? (a) No (b) Yes
  22. 22.🔦 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 copper wire. Does the bulb glow? (a) Yes (b) No
  23. 23.🔦 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 brass key. Does the bulb glow? (a) No (b) Yes
  24. 24.🔦 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
  25. 25.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
  26. 26.🔦 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 steel spoon. 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. Does the bulb glow? (a) Yes (b) No
  28. 28.🔦 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
  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 glass marble. Does the bulb glow? (a) Yes (b) No
  30. 30.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) True (b) False
  31. 31.Which of these means the circuit is closed? (a) a wire has come loose (b) the switch is ON (c) the switch is OFF (d) the bulb is unscrewed
  32. 32.🔦 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
  33. 33.Which of these means the circuit is open? (a) all wires are joined (b) the switch is ON (c) a wire is cut (d) the loop is complete
  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 glass marble. Does the bulb glow? (a) No (b) Yes
  35. 35.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
  36. 36.Which of these means the circuit is closed? (a) a wire is cut (b) a wire has come loose (c) all wires are joined (d) a cell is taken out
  37. 37.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
  38. 38.🔦 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 ruler. Does the bulb glow? (a) No (b) Yes
  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 a dry cork. Does the bulb glow? (a) No (b) Yes
  40. 40.🔦 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

Answer key

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

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