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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 61 · 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 switch (b) the filament (c) the glass (d) the base
  2. 2.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
  3. 3.🔦 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 woollen thread. Does the bulb glow? (a) Yes (b) No
  4. 4.🔦 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
  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 an iron nail. Does the bulb glow? (a) No (b) Yes
  6. 6.🔁 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
  7. 7.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
  8. 8.🔦 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) Yes (b) No
  9. 9.True or false: if the switch is OFF, the circuit is open and no current flows. (a) True (b) False
  10. 10.🔦 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
  11. 11.True or false: if the switch is OFF, the circuit is closed and current flows. (a) False (b) True
  12. 12.🔁 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
  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 metal paper clip. Does the bulb glow? (a) Yes (b) No
  14. 14.True or false: if a wire has come loose, the circuit is open and no current flows. (a) True (b) False
  15. 15.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
  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 rubber eraser. 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 dry cork. Does the bulb glow? (a) No (b) Yes
  18. 18.🔦 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) Yes (b) No
  19. 19.🔦 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 ceramic cup. Does the bulb glow? (a) Yes (b) No
  20. 20.True or false: if the switch is ON, the circuit is closed and current flows. (a) False (b) True
  21. 21.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
  22. 22.Which of these means the circuit is closed? (a) a wire has come loose (b) a cell is taken out (c) the loop is complete (d) the switch is OFF
  23. 23.True or false: if the loop is complete, the circuit is open and no current flows. (a) True (b) False
  24. 24.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
  25. 25.🔦 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
  26. 26.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
  27. 27.True or false: if a wire has come loose, the circuit is closed and current flows. (a) True (b) False
  28. 28.Which of these means the circuit is open? (a) a wire is cut (b) the switch is ON (c) all wires are joined (d) the loop is complete
  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 plastic ruler. Does the bulb glow? (a) No (b) Yes
  30. 30.Which of these means the circuit is open? (a) the switch is ON (b) the loop is complete (c) all wires are joined (d) a wire has come loose
  31. 31.🔁 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
  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 glass marble. Does the bulb glow? (a) No (b) Yes
  33. 33.Which of these means the circuit is closed? (a) the switch is OFF (b) a cell is taken out (c) all wires are joined (d) the bulb is unscrewed
  34. 34.🔦 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
  35. 35.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
  36. 36.🔦 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 steel spoon. Does the bulb glow? (a) Yes (b) No
  37. 37.Which of these means the circuit is open? (a) the switch is ON (b) the bulb is unscrewed (c) the loop is complete (d) all wires are joined
  38. 38.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) the switch is ON (c) a cell is taken out (d) the switch is OFF
  39. 39.🔦 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 wooden stick. Does the bulb glow? (a) Yes (b) No
  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 wooden stick. Does the bulb glow? (a) No (b) Yes

Answer key

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

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