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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 67 · 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 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
  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. A gap in one wire is bridged by an iron nail. Does the bulb glow? (a) Yes (b) No
  3. 3.🔦 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
  4. 4.🔦 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
  5. 5.Which of these means the circuit is closed? (a) a wire is cut (b) the bulb is unscrewed (c) the loop is complete (d) a cell is taken out
  6. 6.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the base (c) the switch (d) the filament
  7. 7.Which of these means the circuit is closed? (a) a cell is taken out (b) a wire has come loose (c) the bulb is unscrewed (d) all wires are joined
  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 metal paper clip. Does the bulb glow? (a) Yes (b) No
  9. 9.🔦 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 plastic straw. Does the bulb glow? (a) Yes (b) No
  10. 10.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
  11. 11.True or false: if the switch is OFF, the circuit is closed and current flows. (a) True (b) False
  12. 12.🔦 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) No (b) Yes
  13. 13.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
  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 paper strip. Does the bulb glow? (a) Yes (b) No
  15. 15.🔁 What must there be for a current to flow? (a) one loose end (b) a complete loop (c) a plastic gap (d) a broken path
  16. 16.🔁 What do we call a circuit with a break in it? (a) a full circuit (b) a closed circuit (c) an open circuit (d) a series circuit
  17. 17.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
  18. 18.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
  19. 19.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
  20. 20.Which of these means the circuit is closed? (a) a cell is taken out (b) a wire has come loose (c) the switch is ON (d) the bulb is unscrewed
  21. 21.🔦 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) No (b) Yes
  22. 22.🔦 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 rubber band. Does the bulb glow? (a) Yes (b) No
  23. 23.Which of these means the circuit is open? (a) the switch is ON (b) the loop is complete (c) the switch is OFF (d) all wires are joined
  24. 24.🔦 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 paper strip. Does the bulb glow? (a) Yes (b) No
  25. 25.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
  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 safety pin. Does the bulb glow? (a) No (b) Yes
  27. 27.🔦 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
  28. 28.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
  29. 29.True or false: if a wire is cut, the circuit is open and no current flows. (a) True (b) False
  30. 30.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
  31. 31.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) both of them (b) none (c) it does not matter (d) only one
  32. 32.Which of these means the circuit is open? (a) the loop is complete (b) the switch is ON (c) the bulb is unscrewed (d) all wires are joined
  33. 33.🔦 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
  34. 34.Which of these means the circuit is open? (a) the switch is ON (b) a wire has come loose (c) all wires are joined (d) the loop is complete
  35. 35.🔦 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
  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 a rubber band. Does the bulb glow? (a) Yes (b) No
  37. 37.🔦 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) No (b) Yes
  38. 38.True or false: if a wire has come loose, the circuit is open and no current flows. (a) False (b) True
  39. 39.🔦 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 safety pin. 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. All the wires are firmly joined. A gap in one wire is bridged by aluminium foil. Does the bulb glow? (a) No (b) Yes

Answer key

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

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