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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 719 · 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 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
  2. 2.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
  3. 3.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
  4. 4.True or false: if a wire has come loose, the circuit is open and no current flows. (a) True (b) False
  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 wooden stick. Does the bulb glow? (a) Yes (b) No
  6. 6.Which of these means the circuit is closed? (a) a wire has come loose (b) the switch is OFF (c) the loop is complete (d) a wire is cut
  7. 7.🔦 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 metal paper clip. Does the bulb glow? (a) Yes (b) No
  8. 8.🔦 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) No (b) Yes
  9. 9.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
  10. 10.True or false: if a cell is taken out, the circuit is closed and current flows. (a) False (b) True
  11. 11.Which of these means the circuit is open? (a) the loop is complete (b) a wire has come loose (c) the switch is ON (d) all wires are joined
  12. 12.🔁 What do we call a circuit with a break in it? (a) a closed circuit (b) an open circuit (c) a series circuit (d) a full circuit
  13. 13.🔦 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
  14. 14.🔦 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
  15. 15.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the filament (c) the switch (d) the base
  16. 16.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
  17. 17.🔁 What must there be for a current to flow? (a) a plastic gap (b) one loose end (c) a complete loop (d) a broken path
  18. 18.True or false: if the switch is OFF, the circuit is closed and current flows. (a) False (b) True
  19. 19.🔦 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 graphite rod. Does the bulb glow? (a) No (b) Yes
  20. 20.True or false: if the loop is complete, the circuit is open and no current flows. (a) True (b) False
  21. 21.🔦 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
  22. 22.🔦 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) Yes (b) No
  23. 23.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
  24. 24.🔦 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
  25. 25.Which of these means the circuit is closed? (a) a cell is taken out (b) the switch is ON (c) the switch is OFF (d) a wire has come loose
  26. 26.🔦 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
  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 ceramic cup. Does the bulb glow? (a) Yes (b) No
  28. 28.Which of these means the circuit is closed? (a) all wires are joined (b) the switch is OFF (c) a wire is cut (d) a wire has come loose
  29. 29.Which of these means the circuit is open? (a) the loop is complete (b) the bulb is unscrewed (c) the switch is ON (d) all wires are joined
  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 steel coin. Does the bulb glow? (a) No (b) Yes
  31. 31.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
  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.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) it does not matter (b) both of them (c) none (d) only one
  34. 34.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
  35. 35.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) False (b) True
  36. 36.True or false: if a cell is taken out, the circuit is open and no current flows. (a) True (b) False
  37. 37.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 is cut
  38. 38.🔦 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) Yes (b) No
  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 plastic straw. Does the bulb glow? (a) No (b) Yes
  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 an iron nail. Does the bulb glow? (a) No (b) Yes

Answer key

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

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