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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 144 · 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. A gap in one wire is bridged by a rubber eraser. Does the bulb glow? (a) No (b) Yes
  2. 2.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
  3. 3.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
  4. 4.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
  5. 5.True or false: if the switch is OFF, the circuit is open and no current flows. (a) True (b) False
  6. 6.🔦 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
  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 paper strip. Does the bulb glow? (a) Yes (b) No
  8. 8.🔦 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 copper wire. Does the bulb glow? (a) Yes (b) No
  9. 9.🔦 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) Yes (b) No
  10. 10.Which of these means the circuit is open? (a) the switch is ON (b) the loop is complete (c) all wires are joined (d) a wire is cut
  11. 11.Which of these means the circuit is closed? (a) a wire is cut (b) a cell is taken out (c) a wire has come loose (d) the loop is complete
  12. 12.True or false: if a wire is cut, the circuit is open and no current flows. (a) False (b) True
  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.🔁 What must there be for a current to flow? (a) a broken path (b) a plastic gap (c) one loose end (d) a complete loop
  15. 15.True or false: if the switch is OFF, 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) Yes (b) No
  17. 17.🔦 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 metal paper clip. Does the bulb glow? (a) No (b) Yes
  18. 18.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
  19. 19.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) a cell is taken out (c) the switch is ON (d) a wire is cut
  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 ruler. Does the bulb glow? (a) Yes (b) No
  21. 21.True or false: if the loop is complete, the circuit is open and no current flows. (a) True (b) False
  22. 22.True or false: if a cell is taken out, the circuit is open and no current flows. (a) False (b) True
  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 rubber band. Does the bulb glow? (a) Yes (b) No
  24. 24.🔁 What do we call a circuit with a break in it? (a) an open circuit (b) a series circuit (c) a full circuit (d) a closed circuit
  25. 25.Which of these means the circuit is open? (a) the loop is complete (b) the bulb is unscrewed (c) the switch is ON (d) all wires are joined
  26. 26.🔦 A circuit has a new cell, a bulb with a broken filament and a switch that is ON. All the wires are firmly joined. Does the bulb glow? (a) Yes (b) No
  27. 27.Which of these means the circuit is open? (a) all wires are joined (b) the switch is OFF (c) the loop is complete (d) the switch is ON
  28. 28.🔦 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
  29. 29.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) False (b) True
  30. 30.🔦 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 aluminium foil. Does the bulb glow? (a) No (b) Yes
  31. 31.🔦 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 ceramic cup. Does the bulb glow? (a) Yes (b) No
  32. 32.Which of these means the circuit is open? (a) the loop is complete (b) a wire has come loose (c) all wires are joined (d) the switch is ON
  33. 33.🔁 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) both of them (d) only one
  34. 34.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the filament (b) the switch (c) the base (d) the glass
  35. 35.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
  36. 36.🔦 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 glass marble. Does the bulb glow? (a) No (b) Yes
  37. 37.Which of these means the circuit is closed? (a) all wires are joined (b) a cell is taken out (c) a wire has come loose (d) the switch is OFF
  38. 38.True or false: if a wire is cut, the circuit is closed and current flows. (a) False (b) True
  39. 39.🔦 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
  40. 40.🔦 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

Answer key

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

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