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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 501 · 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.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
  2. 2.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
  3. 3.🔦 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
  4. 4.🔦 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
  5. 5.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
  6. 6.🔦 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
  7. 7.True or false: if a cell is taken out, the circuit is closed and current flows. (a) False (b) True
  8. 8.Which of these means the circuit is closed? (a) the switch is OFF (b) the switch is ON (c) a wire is cut (d) a wire has come loose
  9. 9.🔁 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) only one (d) none
  10. 10.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
  11. 11.🔦 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
  12. 12.🔦 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 graphite rod. 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 woollen thread. Does the bulb glow? (a) No (b) Yes
  14. 14.🔦 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
  15. 15.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the switch (b) the base (c) the glass (d) the filament
  16. 16.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
  17. 17.Which of these means the circuit is closed? (a) all wires are joined (b) a wire is cut (c) a cell is taken out (d) the switch is OFF
  18. 18.🔁 What do we call a circuit with a break in it? (a) a full circuit (b) an open circuit (c) a closed circuit (d) a series circuit
  19. 19.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
  20. 20.🔦 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 cotton thread. Does the bulb glow? (a) Yes (b) No
  21. 21.True or false: if all wires are joined, the circuit is open and no current flows. (a) False (b) True
  22. 22.🔦 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
  23. 23.🔦 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
  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 paper strip. Does the bulb glow? (a) No (b) Yes
  25. 25.🔁 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
  26. 26.True or false: if the switch is OFF, the circuit is closed and current flows. (a) False (b) True
  27. 27.Which of these means the circuit is open? (a) the bulb is unscrewed (b) the switch is ON (c) the loop is complete (d) all wires are joined
  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) No (b) Yes
  29. 29.🔦 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
  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 graphite rod. Does the bulb glow? (a) No (b) Yes
  31. 31.🔦 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 paper strip. Does the bulb glow? (a) Yes (b) No
  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 wooden stick. Does the bulb glow? (a) Yes (b) No
  33. 33.True or false: if the switch is ON, the circuit is open and no current flows. (a) True (b) False
  34. 34.🔦 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
  35. 35.True or false: if the switch is ON, the circuit is closed and current flows. (a) True (b) False
  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 steel coin. 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. 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
  38. 38.Which of these means the circuit is closed? (a) the switch is OFF (b) the loop is complete (c) a wire has come loose (d) a cell is taken out
  39. 39.🔦 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
  40. 40.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open

Answer key

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

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