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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 927 · 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 loop is complete, the circuit is closed and current flows. (a) True (b) False
  2. 2.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
  3. 3.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
  4. 4.True or false: if a wire is cut, the circuit is closed and current flows. (a) True (b) False
  5. 5.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
  6. 6.🔦 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
  7. 7.🔦 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
  8. 8.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) a wire has come loose (c) all wires are joined (d) the switch is OFF
  9. 9.🔁 What must there be for a current to flow? (a) a complete loop (b) a plastic gap (c) one loose end (d) a broken path
  10. 10.True or false: if all wires are joined, the circuit is closed and current flows. (a) True (b) False
  11. 11.🔦 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
  12. 12.True or false: if the switch is OFF, the circuit is open and no current flows. (a) True (b) False
  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 brass key. 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 cotton thread. Does the bulb glow? (a) Yes (b) No
  15. 15.Which of these means the circuit is open? (a) the switch is ON (b) the loop is complete (c) the bulb is unscrewed (d) all wires are joined
  16. 16.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
  17. 17.🔁 What do we call a circuit with a break in it? (a) a closed circuit (b) a series circuit (c) an open circuit (d) a full circuit
  18. 18.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
  19. 19.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the switch (b) the glass (c) the base (d) the filament
  20. 20.Which of these means the circuit is open? (a) all wires are joined (b) the loop is complete (c) the switch is OFF (d) the switch is ON
  21. 21.🔦 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 ceramic cup. Does the bulb glow? (a) No (b) Yes
  22. 22.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
  23. 23.True or false: if a cell is taken out, the circuit is closed and current flows. (a) False (b) True
  24. 24.True or false: if a wire has come loose, the circuit is open and no current flows. (a) False (b) True
  25. 25.🔦 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 cotton thread. Does the bulb glow? (a) No (b) Yes
  26. 26.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
  27. 27.🔦 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 eraser. Does the bulb glow? (a) No (b) Yes
  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.🔦 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
  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 plastic straw. Does the bulb glow? (a) Yes (b) No
  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 glass marble. Does the bulb glow? (a) No (b) Yes
  32. 32.🔦 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 glass marble. 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.Which of these means the circuit is closed? (a) the loop is complete (b) a cell is taken out (c) the bulb is unscrewed (d) a wire has come loose
  35. 35.🔦 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 graphite rod. 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 cotton thread. Does the bulb glow? (a) Yes (b) No
  37. 37.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
  38. 38.True or false: if a wire is cut, 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 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
  40. 40.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) none (b) only one (c) it does not matter (d) both of them

Answer key

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

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