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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 465 · 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.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) True (b) False
  2. 2.True or false: if a cell is taken out, the circuit is closed and current flows. (a) True (b) False
  3. 3.Which of these means the circuit is closed? (a) a wire has come loose (b) all wires are joined (c) a cell is taken out (d) the switch is OFF
  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) No (b) Yes
  5. 5.🔁 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
  6. 6.🔁 What do we call a circuit with a break in it? (a) a full circuit (b) a closed circuit (c) a series circuit (d) an open circuit
  7. 7.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) the switch is ON (d) a wire has come loose
  8. 8.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
  9. 9.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) the switch is OFF (c) a wire is cut (d) the switch is ON
  10. 10.🔦 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 cotton thread. Does the bulb glow? (a) No (b) Yes
  11. 11.🔦 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
  12. 12.🔦 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
  13. 13.True or false: if the loop is complete, the circuit is open and no current flows. (a) True (b) False
  14. 14.True or false: if all wires are joined, the circuit is closed and current flows. (a) False (b) True
  15. 15.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
  16. 16.True or false: if a cell is taken out, the circuit is open and no current flows. (a) False (b) True
  17. 17.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
  18. 18.🔦 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 plastic straw. Does the bulb glow? (a) Yes (b) No
  19. 19.🔁 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) only one (d) both of them
  20. 20.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
  21. 21.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the switch (b) the filament (c) the base (d) the glass
  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 steel spoon. Does the bulb glow? (a) No (b) Yes
  23. 23.🔦 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
  24. 24.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
  25. 25.🔦 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
  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.🔦 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 glass marble. Does the bulb glow? (a) Yes (b) No
  28. 28.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
  29. 29.Which of these means the circuit is closed? (a) the loop is complete (b) a wire has come loose (c) a wire is cut (d) the switch is OFF
  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 an iron nail. Does the bulb glow? (a) Yes (b) No
  31. 31.True or false: if a wire is cut, the circuit is closed and current flows. (a) False (b) True
  32. 32.🔦 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 steel spoon. Does the bulb glow? (a) Yes (b) No
  33. 33.True or false: if a wire has come loose, the circuit is open and no current flows. (a) True (b) False
  34. 34.🔦 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
  35. 35.🔦 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 graphite rod. Does the bulb glow? (a) No (b) Yes
  36. 36.Which of these means the circuit is open? (a) the bulb is unscrewed (b) the loop is complete (c) all wires are joined (d) the switch is ON
  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. A gap in one wire is bridged by aluminium foil. Does the bulb glow? (a) Yes (b) No
  38. 38.Which of these means the circuit is open? (a) a cell is taken out (b) the loop is complete (c) all wires are joined (d) the switch is ON
  39. 39.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
  40. 40.🔦 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 ruler. Does the bulb glow? (a) Yes (b) No

Answer key

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

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