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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 681 · 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.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the switch (c) the base (d) the filament
  2. 2.🔦 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
  3. 3.Which of these means the circuit is open? (a) all wires are joined (b) the switch is OFF (c) the switch is ON (d) the loop is complete
  4. 4.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
  5. 5.🔦 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
  6. 6.Which of these means the circuit is closed? (a) the switch is ON (b) a wire has come loose (c) the switch is OFF (d) a cell is taken out
  7. 7.🔦 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
  8. 8.Which of these means the circuit is closed? (a) a cell is taken out (b) the bulb is unscrewed (c) all wires are joined (d) a wire has come loose
  9. 9.🔦 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 rubber eraser. Does the bulb glow? (a) No (b) Yes
  10. 10.🔁 What do we call a circuit with a break in it? (a) an open circuit (b) a full circuit (c) a series circuit (d) a closed circuit
  11. 11.Which of these means the circuit is open? (a) all wires are joined (b) the loop is complete (c) a wire has come loose (d) the switch is ON
  12. 12.Which of these means the circuit is closed? (a) the loop is complete (b) a cell is taken out (c) a wire is cut (d) the bulb is unscrewed
  13. 13.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) only one (b) none (c) both of them (d) it does not matter
  14. 14.True or false: if the loop is complete, the circuit is closed and current flows. (a) False (b) True
  15. 15.🔦 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 coin. Does the bulb glow? (a) Yes (b) No
  16. 16.🔦 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
  17. 17.🔦 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
  18. 18.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
  19. 19.🔁 What must there be for a current to flow? (a) a complete loop (b) one loose end (c) a plastic gap (d) a broken path
  20. 20.🔦 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
  21. 21.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
  22. 22.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
  23. 23.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
  24. 24.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
  25. 25.🔦 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
  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 aluminium foil. Does the bulb glow? (a) Yes (b) No
  27. 27.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
  28. 28.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
  29. 29.🔦 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 safety pin. Does the bulb glow? (a) No (b) Yes
  30. 30.🔦 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) No (b) Yes
  31. 31.True or false: if a cell is taken out, the circuit is closed and current flows. (a) True (b) False
  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 steel spoon. 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. A gap in one wire is bridged by aluminium foil. 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. One wire has come loose from the cell. A gap in one wire is bridged by a steel coin. Does the bulb glow? (a) Yes (b) No
  35. 35.Which of these means the circuit is open? (a) a cell is taken out (b) the switch is ON (c) all wires are joined (d) the loop is complete
  36. 36.True or false: if the switch is OFF, the circuit is closed and current flows. (a) False (b) True
  37. 37.🔦 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 copper wire. Does the bulb glow? (a) No (b) Yes
  38. 38.True or false: if a wire is cut, the circuit is open and no current flows. (a) True (b) False
  39. 39.🔦 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 plastic straw. Does the bulb glow? (a) No (b) Yes
  40. 40.True or false: if a wire has come loose, the circuit is closed and current flows. (a) True (b) False

Answer key

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

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