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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 398 · 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.🔁 What must there be for a current to flow? (a) one loose end (b) a broken path (c) a plastic gap (d) a complete loop
  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) No (b) Yes
  3. 3.🔦 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 steel coin. Does the bulb glow? (a) No (b) Yes
  4. 4.Which of these means the circuit is open? (a) a wire is cut (b) the switch is ON (c) the loop is complete (d) all wires are joined
  5. 5.True or false: if a wire is cut, the circuit is closed and current flows. (a) True (b) False
  6. 6.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
  7. 7.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) only one (b) it does not matter (c) none (d) both of them
  8. 8.🔦 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 steel spoon. Does the bulb glow? (a) No (b) Yes
  9. 9.🔦 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
  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 ceramic cup. Does the bulb glow? (a) Yes (b) No
  11. 11.🔦 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
  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 a cotton thread. Does the bulb glow? (a) Yes (b) No
  13. 13.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
  14. 14.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
  15. 15.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
  16. 16.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
  17. 17.🔦 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 metal paper clip. Does the bulb glow? (a) No (b) Yes
  18. 18.🔦 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
  19. 19.🔦 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
  20. 20.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
  21. 21.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
  22. 22.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
  23. 23.True or false: if a wire has come loose, the circuit is closed and current flows. (a) True (b) False
  24. 24.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) a wire has come loose (c) a wire is cut (d) all wires are joined
  25. 25.True or false: if a wire has come loose, the circuit is open and no current flows. (a) False (b) True
  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 plastic ruler. Does the bulb glow? (a) Yes (b) No
  27. 27.🔁 What do we call a circuit with a break in it? (a) a closed circuit (b) a full circuit (c) an open circuit (d) a series circuit
  28. 28.🔦 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 wooden stick. Does the bulb glow? (a) No (b) Yes
  29. 29.Which of these means the circuit is open? (a) the switch is ON (b) all wires are joined (c) a cell is taken out (d) the loop is complete
  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 copper wire. Does the bulb glow? (a) Yes (b) No
  31. 31.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the filament (b) the switch (c) the base (d) the glass
  32. 32.Which of these means the circuit is open? (a) the loop is complete (b) the bulb is unscrewed (c) all wires are joined (d) the switch is ON
  33. 33.Which of these means the circuit is closed? (a) the switch is OFF (b) a cell is taken out (c) a wire has come loose (d) the loop is complete
  34. 34.True or false: if the switch is OFF, the circuit is open and no current flows. (a) True (b) False
  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 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. One wire has come loose from the cell. A gap in one wire is bridged by a plastic ruler. Does the bulb glow? (a) Yes (b) No
  37. 37.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
  38. 38.Which of these means the circuit is open? (a) all wires are joined (b) the switch is ON (c) the loop is complete (d) a wire has come loose
  39. 39.🔦 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 steel spoon. Does the bulb glow? (a) Yes (b) No
  40. 40.🔦 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) Yes (b) No

Answer key

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

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