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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 35 · 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 OFF. 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
  2. 2.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
  3. 3.Which of these means the circuit is closed? (a) the switch is OFF (b) a wire is cut (c) the loop is complete (d) a cell is taken out
  4. 4.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the filament (c) the glass (d) the switch
  5. 5.🔁 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
  6. 6.🔦 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 aluminium foil. Does the bulb glow? (a) No (b) Yes
  7. 7.Which of these means the circuit is open? (a) all wires are joined (b) the loop is complete (c) the bulb is unscrewed (d) the switch is ON
  8. 8.Which of these means the circuit is open? (a) all wires are joined (b) the switch is OFF (c) the switch is ON (d) the loop is complete
  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. Does the bulb glow? (a) No (b) Yes
  10. 10.True or false: if a wire is cut, the circuit is open and no current flows. (a) True (b) False
  11. 11.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
  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 plastic ruler. Does the bulb glow? (a) Yes (b) No
  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 eraser. Does the bulb glow? (a) No (b) Yes
  14. 14.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 is cut
  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 a brass key. Does the bulb glow? (a) No (b) Yes
  16. 16.🔦 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
  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 graphite rod. Does the bulb glow? (a) No (b) Yes
  18. 18.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
  19. 19.True or false: if the loop is complete, the circuit is open and no current flows. (a) False (b) True
  20. 20.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) it does not matter (b) both of them (c) none (d) only one
  21. 21.Which of these means the circuit is open? (a) all wires are joined (b) a wire has come loose (c) the switch is ON (d) the loop is complete
  22. 22.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) a cell is taken out (c) a wire has come loose (d) all wires are joined
  23. 23.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
  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 an iron nail. Does the bulb glow? (a) Yes (b) No
  25. 25.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
  26. 26.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) False (b) True
  27. 27.🔦 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 paper strip. 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. A gap in one wire is bridged by a dry cork. Does the bulb glow? (a) Yes (b) No
  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 copper wire. Does the bulb glow? (a) No (b) Yes
  30. 30.🔦 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 spoon. Does the bulb glow? (a) No (b) Yes
  31. 31.True or false: if all wires are joined, the circuit is open and no current flows. (a) False (b) True
  32. 32.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
  33. 33.True or false: if a cell is taken out, the circuit is closed and current flows. (a) True (b) False
  34. 34.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
  35. 35.🔦 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
  36. 36.🔦 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 woollen thread. 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 safety pin. 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 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 rubber band. Does the bulb glow? (a) No (b) Yes
  40. 40.🔦 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 woollen thread. Does the bulb glow? (a) No (b) Yes

Answer key

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

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