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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 748 · 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. All the wires are firmly joined. Does the bulb glow? (a) Yes (b) No
  2. 2.Which of these means the circuit is open? (a) the loop is complete (b) the switch is ON (c) all wires are joined (d) a wire has come loose
  3. 3.True or false: if the switch is OFF, the circuit is open and no current flows. (a) False (b) True
  4. 4.Which of these means the circuit is closed? (a) a wire has come loose (b) all wires are joined (c) the bulb is unscrewed (d) a cell is taken out
  5. 5.Which of these means the circuit is closed? (a) a cell is taken out (b) a wire has come loose (c) a wire is cut (d) the loop is complete
  6. 6.True or false: if the switch is OFF, the circuit is closed and current flows. (a) True (b) False
  7. 7.🔁 What must there be for a current to flow? (a) one loose end (b) a plastic gap (c) a broken path (d) a complete loop
  8. 8.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
  9. 9.Which of these means the circuit is closed? (a) the switch is ON (b) a wire has come loose (c) the switch is OFF (d) the bulb is unscrewed
  10. 10.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
  11. 11.🔦 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) No (b) Yes
  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. A gap in one wire is bridged by a graphite rod. Does the bulb glow? (a) Yes (b) No
  13. 13.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
  14. 14.🔦 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
  15. 15.True or false: if a wire is cut, the circuit is closed and current flows. (a) True (b) False
  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 plastic straw. Does the bulb glow? (a) No (b) Yes
  17. 17.Which of these means the circuit is open? (a) all wires are joined (b) the loop is complete (c) the switch is ON (d) the bulb is unscrewed
  18. 18.True or false: if a cell is taken out, the circuit is closed and current flows. (a) True (b) False
  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 an iron nail. Does the bulb glow? (a) No (b) Yes
  20. 20.🔦 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 graphite rod. Does the bulb glow? (a) No (b) Yes
  21. 21.🔦 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 metal paper clip. Does the bulb glow? (a) Yes (b) No
  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 rubber band. Does the bulb glow? (a) No (b) Yes
  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 paper strip. Does the bulb glow? (a) No (b) Yes
  24. 24.🔁 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) only one (d) both of them
  25. 25.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
  26. 26.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) True (b) False
  27. 27.True or false: if a wire is cut, the circuit is open and no current flows. (a) False (b) True
  28. 28.🔦 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) Yes (b) No
  29. 29.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
  30. 30.Which of these means the circuit is open? (a) all wires are joined (b) the loop is complete (c) the switch is OFF (d) the switch is ON
  31. 31.🔦 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 brass key. Does the bulb glow? (a) Yes (b) No
  32. 32.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) False (b) True
  33. 33.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
  34. 34.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the filament (c) the base (d) the switch
  35. 35.🔦 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) Yes (b) No
  36. 36.Which of these means the circuit is open? (a) the switch is ON (b) a wire is cut (c) all wires are joined (d) the loop is complete
  37. 37.🔦 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
  38. 38.🔦 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 paper strip. Does the bulb glow? (a) No (b) Yes
  39. 39.🔦 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
  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 steel spoon. Does the bulb glow? (a) No (b) Yes

Answer key

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

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