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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 801 · 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 all wires are joined? (a) closed (b) open
  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 copper wire. Does the bulb glow? (a) No (b) Yes
  3. 3.Which of these means the circuit is open? (a) the switch is ON (b) all wires are joined (c) a wire has come loose (d) the loop is complete
  4. 4.🔦 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 an iron nail. Does the bulb glow? (a) Yes (b) No
  5. 5.🔦 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 spoon. Does the bulb glow? (a) No (b) Yes
  6. 6.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
  7. 7.🔦 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 ceramic cup. Does the bulb glow? (a) Yes (b) No
  8. 8.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
  9. 9.🔦 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
  10. 10.Which of these means the circuit is closed? (a) the switch is OFF (b) a cell is taken out (c) the bulb is unscrewed (d) the switch is ON
  11. 11.🔁 What must there be for a current to flow? (a) one loose end (b) a complete loop (c) a broken path (d) a plastic gap
  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 cotton thread. Does the bulb glow? (a) Yes (b) No
  13. 13.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
  14. 14.🔦 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) Yes (b) No
  15. 15.🔦 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
  16. 16.🔁 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
  17. 17.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the switch (c) the base (d) the filament
  18. 18.Which of these means the circuit is open? (a) the loop is complete (b) the switch is ON (c) all wires are joined (d) the switch is OFF
  19. 19.Which of these means the circuit is closed? (a) all wires are joined (b) a cell is taken out (c) the switch is OFF (d) the bulb is unscrewed
  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 bulb has two contacts. How many must be joined into the loop for it to glow? (a) only one (b) both of them (c) it does not matter (d) none
  22. 22.Which of these means the circuit is closed? (a) the loop is complete (b) a wire is cut (c) the switch is OFF (d) a wire has come loose
  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 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 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
  25. 25.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
  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 paper strip. 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 dry cork. Does the bulb glow? (a) Yes (b) No
  28. 28.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
  29. 29.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
  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 a metal paper clip. Does the bulb glow? (a) No (b) Yes
  31. 31.True or false: if a wire has come loose, the circuit is closed and current flows. (a) True (b) False
  32. 32.True or false: if the switch is ON, the circuit is open and no current flows. (a) True (b) False
  33. 33.True or false: if the switch is OFF, the circuit is closed and current flows. (a) False (b) True
  34. 34.Which of these means the circuit is open? (a) the switch is ON (b) all wires are joined (c) the loop is complete (d) a cell is taken out
  35. 35.🔦 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
  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. Does the bulb glow? (a) No (b) Yes
  37. 37.🔦 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 cotton thread. Does the bulb glow? (a) Yes (b) No
  38. 38.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) True (b) False
  39. 39.Which of these means the circuit is open? (a) the loop is complete (b) a wire is cut (c) the switch is ON (d) all wires are joined
  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 aluminium foil. Does the bulb glow? (a) Yes (b) No

Answer key

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

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