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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 169 · 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 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 plastic ruler. Does the bulb glow? (a) Yes (b) No
  2. 2.🔦 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
  3. 3.🔦 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
  4. 4.🔦 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 copper wire. Does the bulb glow? (a) No (b) Yes
  5. 5.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
  6. 6.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
  7. 7.🔁 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
  8. 8.🔦 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 safety pin. Does the bulb glow? (a) Yes (b) No
  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 brass key. Does the bulb glow? (a) No (b) Yes
  10. 10.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the switch (b) the filament (c) the glass (d) the base
  11. 11.Which of these means the circuit is open? (a) all wires are joined (b) the bulb is unscrewed (c) the switch is ON (d) the loop is complete
  12. 12.🔦 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 an iron nail. 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.Which of these means the circuit is closed? (a) all wires are joined (b) a wire is cut (c) the bulb is unscrewed (d) the switch is OFF
  15. 15.🔦 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) Yes (b) No
  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.True or false: if the loop is complete, the circuit is open and no current flows. (a) True (b) False
  18. 18.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
  19. 19.Which of these means the circuit is open? (a) all wires are joined (b) a wire is cut (c) the switch is ON (d) the loop is complete
  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 wooden stick. Does the bulb glow? (a) No (b) Yes
  21. 21.🔁 What must there be for a current to flow? (a) one loose end (b) a broken path (c) a complete loop (d) a plastic gap
  22. 22.🔦 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
  23. 23.Which of these means the circuit is open? (a) the switch is ON (b) all wires are joined (c) a cell is taken out (d) the loop is complete
  24. 24.🔦 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 ceramic cup. Does the bulb glow? (a) Yes (b) No
  25. 25.Which of these means the circuit is closed? (a) a wire has come loose (b) the loop is complete (c) a cell is taken out (d) the bulb is unscrewed
  26. 26.🔦 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 rubber eraser. Does the bulb glow? (a) Yes (b) No
  27. 27.🔁 What do we call a circuit with a break in it? (a) an open circuit (b) a series circuit (c) a closed circuit (d) a full circuit
  28. 28.True or false: if all wires are joined, the circuit is open and no current flows. (a) False (b) True
  29. 29.🔦 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) 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 copper wire. Does the bulb glow? (a) No (b) Yes
  31. 31.True or false: if a cell is taken out, 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 rubber band. Does the bulb glow? (a) Yes (b) No
  33. 33.Which of these means the circuit is open? (a) the switch is OFF (b) the switch is ON (c) all wires are joined (d) the loop is complete
  34. 34.🔦 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
  35. 35.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
  36. 36.🔦 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
  37. 37.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
  38. 38.🔦 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
  39. 39.True or false: if the switch is OFF, the circuit is closed and current flows. (a) True (b) False
  40. 40.True or false: if the switch is ON, the circuit is closed and current flows. (a) True (b) False

Answer key

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

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