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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 928 · 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.True or false: if all wires are joined, the circuit is open and no current flows. (a) False (b) True
  2. 2.🔦 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
  3. 3.True or false: if a wire has come loose, the circuit is closed and current flows. (a) False (b) True
  4. 4.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
  5. 5.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
  6. 6.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
  7. 7.🔁 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
  8. 8.🔦 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
  9. 9.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) a wire is cut (c) the switch is OFF (d) the switch is ON
  10. 10.🔁 What do we call a circuit with a break in it? (a) a closed circuit (b) an open circuit (c) a series circuit (d) a full circuit
  11. 11.🔦 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 spoon. 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 metal paper clip. Does the bulb glow? (a) No (b) Yes
  13. 13.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 is cut
  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) Yes (b) No
  15. 15.True or false: if a cell is taken out, the circuit is open and no current flows. (a) True (b) False
  16. 16.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
  17. 17.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
  18. 18.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) True (b) False
  19. 19.True or false: if the switch is OFF, the circuit is closed and current flows. (a) True (b) False
  20. 20.Which of these means the circuit is open? (a) all wires are joined (b) the switch is ON (c) the bulb is unscrewed (d) the loop is complete
  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. Does the bulb glow? (a) No (b) Yes
  22. 22.Which of these means the circuit is closed? (a) a wire has come loose (b) a cell is taken out (c) the loop is complete (d) the switch is OFF
  23. 23.Which of these means the circuit is open? (a) the switch is ON (b) a wire has come loose (c) the loop is complete (d) all wires are joined
  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 a brass key. Does the bulb glow? (a) No (b) Yes
  25. 25.🔦 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
  26. 26.🔦 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
  27. 27.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
  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 rubber band. 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 cotton thread. Does the bulb glow? (a) Yes (b) No
  30. 30.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the filament (c) the switch (d) the base
  31. 31.True or false: if the switch is ON, the circuit is open and no current flows. (a) True (b) False
  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 steel coin. 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 a woollen thread. Does the bulb glow? (a) No (b) Yes
  34. 34.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) True (b) False
  35. 35.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
  36. 36.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) it does not matter (b) none (c) both of them (d) only one
  37. 37.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
  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 a dry cork. Does the bulb glow? (a) Yes (b) No
  39. 39.Which of these means the circuit is open? (a) a cell is taken out (b) the switch is ON (c) all wires are joined (d) the loop is complete
  40. 40.🔦 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 aluminium foil. Does the bulb glow? (a) Yes (b) No

Answer key

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

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