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Electronics Worksheet: Simple Circuit – Open and Closed

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

Answer key

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

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