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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 10 · 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 the bulb is unscrewed? (a) open (b) closed
  2. 2.True or false: if all wires are joined, the circuit is closed and current flows. (a) False (b) True
  3. 3.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
  4. 4.🔁 What must there be for a current to flow? (a) a complete loop (b) one loose end (c) a plastic gap (d) a broken path
  5. 5.🔦 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
  6. 6.Which of these means the circuit is closed? (a) the switch is OFF (b) a cell is taken out (c) a wire is cut (d) all wires are joined
  7. 7.🔦 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
  8. 8.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
  9. 9.Which of these means the circuit is open? (a) the loop is complete (b) the switch is ON (c) a wire has come loose (d) all wires are joined
  10. 10.True or false: if the switch is OFF, the circuit is closed and current flows. (a) False (b) True
  11. 11.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
  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 rubber eraser. Does the bulb glow? (a) No (b) Yes
  13. 13.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) a wire is cut (c) the switch is ON (d) a wire has come loose
  14. 14.🔦 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 steel coin. Does the bulb glow? (a) Yes (b) No
  15. 15.Which of these means the circuit is open? (a) the bulb is unscrewed (b) all wires are joined (c) the loop is complete (d) the switch is ON
  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) No (b) Yes
  17. 17.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) both of them (b) it does not matter (c) none (d) only one
  18. 18.🔦 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 glass marble. Does the bulb glow? (a) No (b) Yes
  19. 19.True or false: if a wire has come loose, the circuit is open and no current flows. (a) True (b) False
  20. 20.🔦 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
  21. 21.🔁 What do we call a circuit with a break in it? (a) a full circuit (b) an open circuit (c) a series circuit (d) a closed circuit
  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 graphite rod. Does the bulb glow? (a) Yes (b) No
  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 woollen thread. Does the bulb glow? (a) Yes (b) No
  24. 24.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
  25. 25.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
  26. 26.True or false: if a wire is cut, the circuit is open and no current flows. (a) False (b) True
  27. 27.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
  28. 28.True or false: if a wire has come loose, the circuit is closed and current flows. (a) True (b) False
  29. 29.True or false: if the loop is complete, the circuit is open and no current flows. (a) True (b) False
  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 paper strip. Does the bulb glow? (a) Yes (b) No
  31. 31.True or false: if the loop is complete, the circuit is closed and current flows. (a) True (b) False
  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 woollen thread. Does the bulb glow? (a) No (b) Yes
  33. 33.🔦 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 aluminium foil. Does the bulb glow? (a) Yes (b) No
  34. 34.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
  35. 35.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
  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 copper wire. Does the bulb glow? (a) No (b) Yes
  37. 37.True or false: if a cell is taken out, the circuit is closed and current flows. (a) False (b) True
  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. Does the bulb glow? (a) No (b) Yes
  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 an iron nail. 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. 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

Answer key

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

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