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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 877 · 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) it does not matter (b) none (c) only one (d) both of them
  2. 2.🔦 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
  3. 3.🔦 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 rubber eraser. Does the bulb glow? (a) No (b) Yes
  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. Does the bulb glow? (a) Yes (b) No
  5. 5.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the glass (c) the switch (d) the filament
  6. 6.Which of these means the circuit is closed? (a) the switch is OFF (b) the loop is complete (c) a wire has come loose (d) the bulb is unscrewed
  7. 7.🔁 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
  8. 8.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
  9. 9.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
  10. 10.Which of these means the circuit is open? (a) all wires are joined (b) the loop is complete (c) a cell is taken out (d) the switch is ON
  11. 11.True or false: if a cell is taken out, the circuit is open and no current flows. (a) True (b) False
  12. 12.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
  13. 13.🔦 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
  14. 14.Which of these means the circuit is closed? (a) the switch is OFF (b) the bulb is unscrewed (c) a cell is taken out (d) the switch is ON
  15. 15.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) a wire is cut (d) the switch is ON
  16. 16.True or false: if the loop is complete, the circuit is closed and current flows. (a) False (b) True
  17. 17.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 bulb is unscrewed
  18. 18.🔦 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
  19. 19.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
  20. 20.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
  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 a steel spoon. Does the bulb glow? (a) No (b) Yes
  22. 22.True or false: if a wire has come loose, the circuit is open and no current flows. (a) True (b) False
  23. 23.🔦 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 band. 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) No (b) Yes
  25. 25.True or false: if a cell is taken out, the circuit is closed and current flows. (a) False (b) True
  26. 26.Which of these means the circuit is closed? (a) a cell is taken out (b) a wire is cut (c) the bulb is unscrewed (d) all wires are joined
  27. 27.🔦 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) No (b) Yes
  28. 28.🔁 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
  29. 29.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
  30. 30.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
  31. 31.🔦 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
  32. 32.🔦 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
  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. Does the bulb glow? (a) Yes (b) No
  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 plastic ruler. Does the bulb glow? (a) No (b) Yes
  35. 35.🔦 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
  36. 36.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
  37. 37.🔦 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
  38. 38.True or false: if all wires are joined, the circuit is closed and current flows. (a) True (b) False
  39. 39.Which of these means the circuit is open? (a) a wire has come loose (b) the loop is complete (c) the switch is ON (d) all wires are joined
  40. 40.True or false: if a wire is cut, the circuit is closed and current flows. (a) True (b) False

Answer key

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

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