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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 971 · 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 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
  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 metal paper clip. Does the bulb glow? (a) No (b) Yes
  3. 3.🔁 What do we call a circuit with a break in it? (a) a full circuit (b) a series circuit (c) an open circuit (d) a closed circuit
  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 rubber band. Does the bulb glow? (a) Yes (b) No
  5. 5.True or false: if a cell is taken out, the circuit is open and no current flows. (a) False (b) True
  6. 6.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) a cell is taken out (c) the loop is complete (d) the switch is OFF
  7. 7.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
  8. 8.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the glass (c) the switch (d) the filament
  9. 9.🔁 What must there be for a current to flow? (a) one loose end (b) a plastic gap (c) a complete loop (d) a broken path
  10. 10.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
  11. 11.Which of these means the circuit is closed? (a) a wire is cut (b) the switch is OFF (c) a cell is taken out (d) all wires are joined
  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. Does the bulb glow? (a) Yes (b) No
  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 rubber eraser. Does the bulb glow? (a) Yes (b) No
  14. 14.🔦 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 safety pin. Does the bulb glow? (a) No (b) Yes
  15. 15.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
  16. 16.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
  17. 17.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
  18. 18.🔦 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
  19. 19.Which of these means the circuit is open? (a) the switch is OFF (b) the loop is complete (c) all wires are joined (d) the switch is ON
  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 woollen thread. Does the bulb glow? (a) Yes (b) No
  21. 21.🔦 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
  22. 22.True or false: if all wires are joined, the circuit is closed and 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 graphite rod. Does the bulb glow? (a) No (b) Yes
  24. 24.True or false: if the loop is complete, the circuit is closed and current flows. (a) True (b) False
  25. 25.Which of these means the circuit is closed? (a) the switch is ON (b) a wire is cut (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. Does the bulb glow? (a) Yes (b) No
  27. 27.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
  28. 28.🔦 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
  29. 29.True or false: if the switch is OFF, the circuit is closed and current flows. (a) True (b) False
  30. 30.🔦 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 woollen thread. Does the bulb glow? (a) Yes (b) No
  31. 31.Which of these means the circuit is open? (a) the switch is ON (b) the loop is complete (c) all wires are joined (d) the bulb is unscrewed
  32. 32.Which of these means the circuit is open? (a) all wires are joined (b) the switch is ON (c) a wire is cut (d) the loop is complete
  33. 33.🔦 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 woollen thread. Does the bulb glow? (a) No (b) Yes
  34. 34.🔦 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
  35. 35.🔦 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
  36. 36.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 has come loose
  37. 37.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
  38. 38.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
  39. 39.🔦 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
  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 a brass key. Does the bulb glow? (a) No (b) Yes

Answer key

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

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