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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 667 · 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 glass (b) the base (c) the filament (d) the switch
  2. 2.🔦 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) No (b) Yes
  3. 3.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
  4. 4.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
  5. 5.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) none (b) only one (c) it does not matter (d) both of them
  6. 6.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
  7. 7.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) False (b) True
  8. 8.Which of these means the circuit is closed? (a) a cell is taken out (b) the bulb is unscrewed (c) a wire is cut (d) the switch is ON
  9. 9.Which of these means the circuit is closed? (a) the switch is OFF (b) all wires are joined (c) a wire is cut (d) a wire has come loose
  10. 10.🔦 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 an iron nail. Does the bulb glow? (a) No (b) Yes
  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 brass key. Does the bulb glow? (a) Yes (b) No
  12. 12.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
  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 glass marble. Does the bulb glow? (a) Yes (b) No
  14. 14.Which of these means the circuit is closed? (a) a wire has come loose (b) a cell is taken out (c) the switch is OFF (d) the loop is complete
  15. 15.True or false: if a cell is taken out, the circuit is closed and current flows. (a) True (b) False
  16. 16.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
  17. 17.True or false: if a wire has come loose, the circuit is open and no current flows. (a) True (b) False
  18. 18.Which of these means the circuit is open? (a) the loop is complete (b) a cell is taken out (c) all wires are joined (d) the switch is ON
  19. 19.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
  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) 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 glass marble. Does the bulb glow? (a) No (b) Yes
  22. 22.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
  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 paper strip. Does the bulb glow? (a) Yes (b) No
  24. 24.🔦 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 graphite rod. Does the bulb glow? (a) No (b) Yes
  25. 25.True or false: if the loop is complete, the circuit is closed and current flows. (a) True (b) False
  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 wooden stick. 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. 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
  28. 28.🔁 What must there be for a current to flow? (a) a plastic gap (b) a complete loop (c) a broken path (d) one loose end
  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 safety pin. Does the bulb glow? (a) No (b) Yes
  30. 30.True or false: if the loop is complete, the circuit is open and no current flows. (a) True (b) False
  31. 31.Which of these means the circuit is open? (a) the loop is complete (b) a wire has come loose (c) the switch is ON (d) all wires are joined
  32. 32.🔦 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 safety pin. Does the bulb glow? (a) Yes (b) No
  33. 33.🔦 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
  34. 34.🔦 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
  35. 35.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
  36. 36.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
  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 paper strip. Does the bulb glow? (a) No (b) Yes
  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 an iron nail. Does the bulb glow? (a) No (b) Yes
  39. 39.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
  40. 40.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open

Answer key

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

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